1  /**
   2   * Creates a continuation function with some arguments already applied.
   3   *
   4   * Useful as a shorthand when combined with other control flow functions. Any
   5   * arguments passed to the returned function are added to the arguments
   6   * originally passed to apply.
   7   *
   8   * @name apply
   9   * @static
  10   * @memberOf module:Utils
  11   * @method
  12   * @category Util
  13   * @param {Function} fn - The function you want to eventually apply all
  14   * arguments to. Invokes with (arguments...).
  15   * @param {...*} arguments... - Any number of arguments to automatically apply
  16   * when the continuation is called.
  17   * @returns {Function} the partially-applied function
  18   * @example
  19   *
  20   * // using apply
  21   * async.parallel([
  22   *     async.apply(fs.writeFile, 'testfile1', 'test1'),
  23   *     async.apply(fs.writeFile, 'testfile2', 'test2')
  24   * ]);
  25   *
  26   *
  27   * // the same process without using apply
  28   * async.parallel([
  29   *     function(callback) {
  30   *         fs.writeFile('testfile1', 'test1', callback);
  31   *     },
  32   *     function(callback) {
  33   *         fs.writeFile('testfile2', 'test2', callback);
  34   *     }
  35   * ]);
  36   *
  37   * // It's possible to pass any number of additional arguments when calling the
  38   * // continuation:
  39   *
  40   * node> var fn = async.apply(sys.puts, 'one');
  41   * node> fn('two', 'three');
  42   * one
  43   * two
  44   * three
  45   */
  46  function apply(fn, ...args) {
  47      return (...callArgs) => fn(...args,...callArgs);
  48  }
  49  
  50  function initialParams (fn) {
  51      return function (...args/*, callback*/) {
  52          var callback = args.pop();
  53          return fn.call(this, args, callback);
  54      };
  55  }
  56  
  57  /* istanbul ignore file */
  58  
  59  var hasSetImmediate = typeof setImmediate === 'function' && setImmediate;
  60  var hasNextTick = typeof process === 'object' && typeof process.nextTick === 'function';
  61  
  62  function fallback(fn) {
  63      setTimeout(fn, 0);
  64  }
  65  
  66  function wrap(defer) {
  67      return (fn, ...args) => defer(() => fn(...args));
  68  }
  69  
  70  var _defer;
  71  
  72  if (hasSetImmediate) {
  73      _defer = setImmediate;
  74  } else if (hasNextTick) {
  75      _defer = process.nextTick;
  76  } else {
  77      _defer = fallback;
  78  }
  79  
  80  var setImmediate$1 = wrap(_defer);
  81  
  82  /**
  83   * Take a sync function and make it async, passing its return value to a
  84   * callback. This is useful for plugging sync functions into a waterfall,
  85   * series, or other async functions. Any arguments passed to the generated
  86   * function will be passed to the wrapped function (except for the final
  87   * callback argument). Errors thrown will be passed to the callback.
  88   *
  89   * If the function passed to `asyncify` returns a Promise, that promises's
  90   * resolved/rejected state will be used to call the callback, rather than simply
  91   * the synchronous return value.
  92   *
  93   * This also means you can asyncify ES2017 `async` functions.
  94   *
  95   * @name asyncify
  96   * @static
  97   * @memberOf module:Utils
  98   * @method
  99   * @alias wrapSync
 100   * @category Util
 101   * @param {Function} func - The synchronous function, or Promise-returning
 102   * function to convert to an {@link AsyncFunction}.
 103   * @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
 104   * invoked with `(args..., callback)`.
 105   * @example
 106   *
 107   * // passing a regular synchronous function
 108   * async.waterfall([
 109   *     async.apply(fs.readFile, filename, "utf8"),
 110   *     async.asyncify(JSON.parse),
 111   *     function (data, next) {
 112   *         // data is the result of parsing the text.
 113   *         // If there was a parsing error, it would have been caught.
 114   *     }
 115   * ], callback);
 116   *
 117   * // passing a function returning a promise
 118   * async.waterfall([
 119   *     async.apply(fs.readFile, filename, "utf8"),
 120   *     async.asyncify(function (contents) {
 121   *         return db.model.create(contents);
 122   *     }),
 123   *     function (model, next) {
 124   *         // `model` is the instantiated model object.
 125   *         // If there was an error, this function would be skipped.
 126   *     }
 127   * ], callback);
 128   *
 129   * // es2017 example, though `asyncify` is not needed if your JS environment
 130   * // supports async functions out of the box
 131   * var q = async.queue(async.asyncify(async function(file) {
 132   *     var intermediateStep = await processFile(file);
 133   *     return await somePromise(intermediateStep)
 134   * }));
 135   *
 136   * q.push(files);
 137   */
 138  function asyncify(func) {
 139      if (isAsync(func)) {
 140          return function (...args/*, callback*/) {
 141              const callback = args.pop();
 142              const promise = func.apply(this, args);
 143              return handlePromise(promise, callback)
 144          }
 145      }
 146  
 147      return initialParams(function (args, callback) {
 148          var result;
 149          try {
 150              result = func.apply(this, args);
 151          } catch (e) {
 152              return callback(e);
 153          }
 154          // if result is Promise object
 155          if (result && typeof result.then === 'function') {
 156              return handlePromise(result, callback)
 157          } else {
 158              callback(null, result);
 159          }
 160      });
 161  }
 162  
 163  function handlePromise(promise, callback) {
 164      return promise.then(value => {
 165          invokeCallback(callback, null, value);
 166      }, err => {
 167          invokeCallback(callback, err && err.message ? err : new Error(err));
 168      });
 169  }
 170  
 171  function invokeCallback(callback, error, value) {
 172      try {
 173          callback(error, value);
 174      } catch (err) {
 175          setImmediate$1(e => { throw e }, err);
 176      }
 177  }
 178  
 179  function isAsync(fn) {
 180      return fn[Symbol.toStringTag] === 'AsyncFunction';
 181  }
 182  
 183  function isAsyncGenerator(fn) {
 184      return fn[Symbol.toStringTag] === 'AsyncGenerator';
 185  }
 186  
 187  function isAsyncIterable(obj) {
 188      return typeof obj[Symbol.asyncIterator] === 'function';
 189  }
 190  
 191  function wrapAsync(asyncFn) {
 192      if (typeof asyncFn !== 'function') throw new Error('expected a function')
 193      return isAsync(asyncFn) ? asyncify(asyncFn) : asyncFn;
 194  }
 195  
 196  // conditionally promisify a function.
 197  // only return a promise if a callback is omitted
 198  function awaitify (asyncFn, arity = asyncFn.length) {
 199      if (!arity) throw new Error('arity is undefined')
 200      function awaitable (...args) {
 201          if (typeof args[arity - 1] === 'function') {
 202              return asyncFn.apply(this, args)
 203          }
 204  
 205          return new Promise((resolve, reject) => {
 206              args[arity - 1] = (err, ...cbArgs) => {
 207                  if (err) return reject(err)
 208                  resolve(cbArgs.length > 1 ? cbArgs : cbArgs[0]);
 209              };
 210              asyncFn.apply(this, args);
 211          })
 212      }
 213  
 214      return awaitable
 215  }
 216  
 217  function applyEach (eachfn) {
 218      return function applyEach(fns, ...callArgs) {
 219          const go = awaitify(function (callback) {
 220              var that = this;
 221              return eachfn(fns, (fn, cb) => {
 222                  wrapAsync(fn).apply(that, callArgs.concat(cb));
 223              }, callback);
 224          });
 225          return go;
 226      };
 227  }
 228  
 229  function _asyncMap(eachfn, arr, iteratee, callback) {
 230      arr = arr || [];
 231      var results = [];
 232      var counter = 0;
 233      var _iteratee = wrapAsync(iteratee);
 234  
 235      return eachfn(arr, (value, _, iterCb) => {
 236          var index = counter++;
 237          _iteratee(value, (err, v) => {
 238              results[index] = v;
 239              iterCb(err);
 240          });
 241      }, err => {
 242          callback(err, results);
 243      });
 244  }
 245  
 246  function isArrayLike(value) {
 247      return value &&
 248          typeof value.length === 'number' &&
 249          value.length >= 0 &&
 250          value.length % 1 === 0;
 251  }
 252  
 253  // A temporary value used to identify if the loop should be broken.
 254  // See #1064, #1293
 255  const breakLoop = {};
 256  
 257  function once(fn) {
 258      function wrapper (...args) {
 259          if (fn === null) return;
 260          var callFn = fn;
 261          fn = null;
 262          callFn.apply(this, args);
 263      }
 264      Object.assign(wrapper, fn);
 265      return wrapper
 266  }
 267  
 268  function getIterator (coll) {
 269      return coll[Symbol.iterator] && coll[Symbol.iterator]();
 270  }
 271  
 272  function createArrayIterator(coll) {
 273      var i = -1;
 274      var len = coll.length;
 275      return function next() {
 276          return ++i < len ? {value: coll[i], key: i} : null;
 277      }
 278  }
 279  
 280  function createES2015Iterator(iterator) {
 281      var i = -1;
 282      return function next() {
 283          var item = iterator.next();
 284          if (item.done)
 285              return null;
 286          i++;
 287          return {value: item.value, key: i};
 288      }
 289  }
 290  
 291  function createObjectIterator(obj) {
 292      var okeys = obj ? Object.keys(obj) : [];
 293      var i = -1;
 294      var len = okeys.length;
 295      return function next() {
 296          var key = okeys[++i];
 297          return i < len ? {value: obj[key], key} : null;
 298      };
 299  }
 300  
 301  function createIterator(coll) {
 302      if (isArrayLike(coll)) {
 303          return createArrayIterator(coll);
 304      }
 305  
 306      var iterator = getIterator(coll);
 307      return iterator ? createES2015Iterator(iterator) : createObjectIterator(coll);
 308  }
 309  
 310  function onlyOnce(fn) {
 311      return function (...args) {
 312          if (fn === null) throw new Error("Callback was already called.");
 313          var callFn = fn;
 314          fn = null;
 315          callFn.apply(this, args);
 316      };
 317  }
 318  
 319  // for async generators
 320  function asyncEachOfLimit(generator, limit, iteratee, callback) {
 321      let done = false;
 322      let canceled = false;
 323      let awaiting = false;
 324      let running = 0;
 325      let idx = 0;
 326  
 327      function replenish() {
 328          //console.log('replenish')
 329          if (running >= limit || awaiting || done) return
 330          //console.log('replenish awaiting')
 331          awaiting = true;
 332          generator.next().then(({value, done: iterDone}) => {
 333              //console.log('got value', value)
 334              if (canceled || done) return
 335              awaiting = false;
 336              if (iterDone) {
 337                  done = true;
 338                  if (running <= 0) {
 339                      //console.log('done nextCb')
 340                      callback(null);
 341                  }
 342                  return;
 343              }
 344              running++;
 345              iteratee(value, idx, iterateeCallback);
 346              idx++;
 347              replenish();
 348          }).catch(handleError);
 349      }
 350  
 351      function iterateeCallback(err, result) {
 352          //console.log('iterateeCallback')
 353          running -= 1;
 354          if (canceled) return
 355          if (err) return handleError(err)
 356  
 357          if (err === false) {
 358              done = true;
 359              canceled = true;
 360              return
 361          }
 362  
 363          if (result === breakLoop || (done && running <= 0)) {
 364              done = true;
 365              //console.log('done iterCb')
 366              return callback(null);
 367          }
 368          replenish();
 369      }
 370  
 371      function handleError(err) {
 372          if (canceled) return
 373          awaiting = false;
 374          done = true;
 375          callback(err);
 376      }
 377  
 378      replenish();
 379  }
 380  
 381  var eachOfLimit = (limit) => {
 382      return (obj, iteratee, callback) => {
 383          callback = once(callback);
 384          if (limit <= 0) {
 385              throw new RangeError('concurrency limit cannot be less than 1')
 386          }
 387          if (!obj) {
 388              return callback(null);
 389          }
 390          if (isAsyncGenerator(obj)) {
 391              return asyncEachOfLimit(obj, limit, iteratee, callback)
 392          }
 393          if (isAsyncIterable(obj)) {
 394              return asyncEachOfLimit(obj[Symbol.asyncIterator](), limit, iteratee, callback)
 395          }
 396          var nextElem = createIterator(obj);
 397          var done = false;
 398          var canceled = false;
 399          var running = 0;
 400          var looping = false;
 401  
 402          function iterateeCallback(err, value) {
 403              if (canceled) return
 404              running -= 1;
 405              if (err) {
 406                  done = true;
 407                  callback(err);
 408              }
 409              else if (err === false) {
 410                  done = true;
 411                  canceled = true;
 412              }
 413              else if (value === breakLoop || (done && running <= 0)) {
 414                  done = true;
 415                  return callback(null);
 416              }
 417              else if (!looping) {
 418                  replenish();
 419              }
 420          }
 421  
 422          function replenish () {
 423              looping = true;
 424              while (running < limit && !done) {
 425                  var elem = nextElem();
 426                  if (elem === null) {
 427                      done = true;
 428                      if (running <= 0) {
 429                          callback(null);
 430                      }
 431                      return;
 432                  }
 433                  running += 1;
 434                  iteratee(elem.value, elem.key, onlyOnce(iterateeCallback));
 435              }
 436              looping = false;
 437          }
 438  
 439          replenish();
 440      };
 441  };
 442  
 443  /**
 444   * The same as [`eachOf`]{@link module:Collections.eachOf} but runs a maximum of `limit` async operations at a
 445   * time.
 446   *
 447   * @name eachOfLimit
 448   * @static
 449   * @memberOf module:Collections
 450   * @method
 451   * @see [async.eachOf]{@link module:Collections.eachOf}
 452   * @alias forEachOfLimit
 453   * @category Collection
 454   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 455   * @param {number} limit - The maximum number of async operations at a time.
 456   * @param {AsyncFunction} iteratee - An async function to apply to each
 457   * item in `coll`. The `key` is the item's key, or index in the case of an
 458   * array.
 459   * Invoked with (item, key, callback).
 460   * @param {Function} [callback] - A callback which is called when all
 461   * `iteratee` functions have finished, or an error occurs. Invoked with (err).
 462   * @returns {Promise} a promise, if a callback is omitted
 463   */
 464  function eachOfLimit$1(coll, limit, iteratee, callback) {
 465      return eachOfLimit(limit)(coll, wrapAsync(iteratee), callback);
 466  }
 467  
 468  var eachOfLimit$2 = awaitify(eachOfLimit$1, 4);
 469  
 470  // eachOf implementation optimized for array-likes
 471  function eachOfArrayLike(coll, iteratee, callback) {
 472      callback = once(callback);
 473      var index = 0,
 474          completed = 0,
 475          {length} = coll,
 476          canceled = false;
 477      if (length === 0) {
 478          callback(null);
 479      }
 480  
 481      function iteratorCallback(err, value) {
 482          if (err === false) {
 483              canceled = true;
 484          }
 485          if (canceled === true) return
 486          if (err) {
 487              callback(err);
 488          } else if ((++completed === length) || value === breakLoop) {
 489              callback(null);
 490          }
 491      }
 492  
 493      for (; index < length; index++) {
 494          iteratee(coll[index], index, onlyOnce(iteratorCallback));
 495      }
 496  }
 497  
 498  // a generic version of eachOf which can handle array, object, and iterator cases.
 499  function eachOfGeneric (coll, iteratee, callback) {
 500      return eachOfLimit$2(coll, Infinity, iteratee, callback);
 501  }
 502  
 503  /**
 504   * Like [`each`]{@link module:Collections.each}, except that it passes the key (or index) as the second argument
 505   * to the iteratee.
 506   *
 507   * @name eachOf
 508   * @static
 509   * @memberOf module:Collections
 510   * @method
 511   * @alias forEachOf
 512   * @category Collection
 513   * @see [async.each]{@link module:Collections.each}
 514   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 515   * @param {AsyncFunction} iteratee - A function to apply to each
 516   * item in `coll`.
 517   * The `key` is the item's key, or index in the case of an array.
 518   * Invoked with (item, key, callback).
 519   * @param {Function} [callback] - A callback which is called when all
 520   * `iteratee` functions have finished, or an error occurs. Invoked with (err).
 521   * @returns {Promise} a promise, if a callback is omitted
 522   * @example
 523   *
 524   * var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"};
 525   * var configs = {};
 526   *
 527   * async.forEachOf(obj, function (value, key, callback) {
 528   *     fs.readFile(__dirname + value, "utf8", function (err, data) {
 529   *         if (err) return callback(err);
 530   *         try {
 531   *             configs[key] = JSON.parse(data);
 532   *         } catch (e) {
 533   *             return callback(e);
 534   *         }
 535   *         callback();
 536   *     });
 537   * }, function (err) {
 538   *     if (err) console.error(err.message);
 539   *     // configs is now a map of JSON data
 540   *     doSomethingWith(configs);
 541   * });
 542   */
 543  function eachOf(coll, iteratee, callback) {
 544      var eachOfImplementation = isArrayLike(coll) ? eachOfArrayLike : eachOfGeneric;
 545      return eachOfImplementation(coll, wrapAsync(iteratee), callback);
 546  }
 547  
 548  var eachOf$1 = awaitify(eachOf, 3);
 549  
 550  /**
 551   * Produces a new collection of values by mapping each value in `coll` through
 552   * the `iteratee` function. The `iteratee` is called with an item from `coll`
 553   * and a callback for when it has finished processing. Each of these callback
 554   * takes 2 arguments: an `error`, and the transformed item from `coll`. If
 555   * `iteratee` passes an error to its callback, the main `callback` (for the
 556   * `map` function) is immediately called with the error.
 557   *
 558   * Note, that since this function applies the `iteratee` to each item in
 559   * parallel, there is no guarantee that the `iteratee` functions will complete
 560   * in order. However, the results array will be in the same order as the
 561   * original `coll`.
 562   *
 563   * If `map` is passed an Object, the results will be an Array.  The results
 564   * will roughly be in the order of the original Objects' keys (but this can
 565   * vary across JavaScript engines).
 566   *
 567   * @name map
 568   * @static
 569   * @memberOf module:Collections
 570   * @method
 571   * @category Collection
 572   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 573   * @param {AsyncFunction} iteratee - An async function to apply to each item in
 574   * `coll`.
 575   * The iteratee should complete with the transformed item.
 576   * Invoked with (item, callback).
 577   * @param {Function} [callback] - A callback which is called when all `iteratee`
 578   * functions have finished, or an error occurs. Results is an Array of the
 579   * transformed items from the `coll`. Invoked with (err, results).
 580   * @returns {Promise} a promise, if no callback is passed
 581   * @example
 582   *
 583   * async.map(['file1','file2','file3'], fs.stat, function(err, results) {
 584   *     // results is now an array of stats for each file
 585   * });
 586   */
 587  function map (coll, iteratee, callback) {
 588      return _asyncMap(eachOf$1, coll, iteratee, callback)
 589  }
 590  var map$1 = awaitify(map, 3);
 591  
 592  /**
 593   * Applies the provided arguments to each function in the array, calling
 594   * `callback` after all functions have completed. If you only provide the first
 595   * argument, `fns`, then it will return a function which lets you pass in the
 596   * arguments as if it were a single function call. If more arguments are
 597   * provided, `callback` is required while `args` is still optional. The results
 598   * for each of the applied async functions are passed to the final callback
 599   * as an array.
 600   *
 601   * @name applyEach
 602   * @static
 603   * @memberOf module:ControlFlow
 604   * @method
 605   * @category Control Flow
 606   * @param {Array|Iterable|AsyncIterable|Object} fns - A collection of {@link AsyncFunction}s
 607   * to all call with the same arguments
 608   * @param {...*} [args] - any number of separate arguments to pass to the
 609   * function.
 610   * @param {Function} [callback] - the final argument should be the callback,
 611   * called when all functions have completed processing.
 612   * @returns {AsyncFunction} - Returns a function that takes no args other than
 613   * an optional callback, that is the result of applying the `args` to each
 614   * of the functions.
 615   * @example
 616   *
 617   * const appliedFn = async.applyEach([enableSearch, updateSchema], 'bucket')
 618   *
 619   * appliedFn((err, results) => {
 620   *     // results[0] is the results for `enableSearch`
 621   *     // results[1] is the results for `updateSchema`
 622   * });
 623   *
 624   * // partial application example:
 625   * async.each(
 626   *     buckets,
 627   *     async (bucket) => async.applyEach([enableSearch, updateSchema], bucket)(),
 628   *     callback
 629   * );
 630   */
 631  var applyEach$1 = applyEach(map$1);
 632  
 633  /**
 634   * The same as [`eachOf`]{@link module:Collections.eachOf} but runs only a single async operation at a time.
 635   *
 636   * @name eachOfSeries
 637   * @static
 638   * @memberOf module:Collections
 639   * @method
 640   * @see [async.eachOf]{@link module:Collections.eachOf}
 641   * @alias forEachOfSeries
 642   * @category Collection
 643   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 644   * @param {AsyncFunction} iteratee - An async function to apply to each item in
 645   * `coll`.
 646   * Invoked with (item, key, callback).
 647   * @param {Function} [callback] - A callback which is called when all `iteratee`
 648   * functions have finished, or an error occurs. Invoked with (err).
 649   * @returns {Promise} a promise, if a callback is omitted
 650   */
 651  function eachOfSeries(coll, iteratee, callback) {
 652      return eachOfLimit$2(coll, 1, iteratee, callback)
 653  }
 654  var eachOfSeries$1 = awaitify(eachOfSeries, 3);
 655  
 656  /**
 657   * The same as [`map`]{@link module:Collections.map} but runs only a single async operation at a time.
 658   *
 659   * @name mapSeries
 660   * @static
 661   * @memberOf module:Collections
 662   * @method
 663   * @see [async.map]{@link module:Collections.map}
 664   * @category Collection
 665   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
 666   * @param {AsyncFunction} iteratee - An async function to apply to each item in
 667   * `coll`.
 668   * The iteratee should complete with the transformed item.
 669   * Invoked with (item, callback).
 670   * @param {Function} [callback] - A callback which is called when all `iteratee`
 671   * functions have finished, or an error occurs. Results is an array of the
 672   * transformed items from the `coll`. Invoked with (err, results).
 673   * @returns {Promise} a promise, if no callback is passed
 674   */
 675  function mapSeries (coll, iteratee, callback) {
 676      return _asyncMap(eachOfSeries$1, coll, iteratee, callback)
 677  }
 678  var mapSeries$1 = awaitify(mapSeries, 3);
 679  
 680  /**
 681   * The same as [`applyEach`]{@link module:ControlFlow.applyEach} but runs only a single async operation at a time.
 682   *
 683   * @name applyEachSeries
 684   * @static
 685   * @memberOf module:ControlFlow
 686   * @method
 687   * @see [async.applyEach]{@link module:ControlFlow.applyEach}
 688   * @category Control Flow
 689   * @param {Array|Iterable|AsyncIterable|Object} fns - A collection of {@link AsyncFunction}s to all
 690   * call with the same arguments
 691   * @param {...*} [args] - any number of separate arguments to pass to the
 692   * function.
 693   * @param {Function} [callback] - the final argument should be the callback,
 694   * called when all functions have completed processing.
 695   * @returns {AsyncFunction} - A function, that when called, is the result of
 696   * appling the `args` to the list of functions.  It takes no args, other than
 697   * a callback.
 698   */
 699  var applyEachSeries = applyEach(mapSeries$1);
 700  
 701  const PROMISE_SYMBOL = Symbol('promiseCallback');
 702  
 703  function promiseCallback () {
 704      let resolve, reject;
 705      function callback (err, ...args) {
 706          if (err) return reject(err)
 707          resolve(args.length > 1 ? args : args[0]);
 708      }
 709  
 710      callback[PROMISE_SYMBOL] = new Promise((res, rej) => {
 711          resolve = res,
 712          reject = rej;
 713      });
 714  
 715      return callback
 716  }
 717  
 718  /**
 719   * Determines the best order for running the {@link AsyncFunction}s in `tasks`, based on
 720   * their requirements. Each function can optionally depend on other functions
 721   * being completed first, and each function is run as soon as its requirements
 722   * are satisfied.
 723   *
 724   * If any of the {@link AsyncFunction}s pass an error to their callback, the `auto` sequence
 725   * will stop. Further tasks will not execute (so any other functions depending
 726   * on it will not run), and the main `callback` is immediately called with the
 727   * error.
 728   *
 729   * {@link AsyncFunction}s also receive an object containing the results of functions which
 730   * have completed so far as the first argument, if they have dependencies. If a
 731   * task function has no dependencies, it will only be passed a callback.
 732   *
 733   * @name auto
 734   * @static
 735   * @memberOf module:ControlFlow
 736   * @method
 737   * @category Control Flow
 738   * @param {Object} tasks - An object. Each of its properties is either a
 739   * function or an array of requirements, with the {@link AsyncFunction} itself the last item
 740   * in the array. The object's key of a property serves as the name of the task
 741   * defined by that property, i.e. can be used when specifying requirements for
 742   * other tasks. The function receives one or two arguments:
 743   * * a `results` object, containing the results of the previously executed
 744   *   functions, only passed if the task has any dependencies,
 745   * * a `callback(err, result)` function, which must be called when finished,
 746   *   passing an `error` (which can be `null`) and the result of the function's
 747   *   execution.
 748   * @param {number} [concurrency=Infinity] - An optional `integer` for
 749   * determining the maximum number of tasks that can be run in parallel. By
 750   * default, as many as possible.
 751   * @param {Function} [callback] - An optional callback which is called when all
 752   * the tasks have been completed. It receives the `err` argument if any `tasks`
 753   * pass an error to their callback. Results are always returned; however, if an
 754   * error occurs, no further `tasks` will be performed, and the results object
 755   * will only contain partial results. Invoked with (err, results).
 756   * @returns {Promise} a promise, if a callback is not passed
 757   * @example
 758   *
 759   * async.auto({
 760   *     // this function will just be passed a callback
 761   *     readData: async.apply(fs.readFile, 'data.txt', 'utf-8'),
 762   *     showData: ['readData', function(results, cb) {
 763   *         // results.readData is the file's contents
 764   *         // ...
 765   *     }]
 766   * }, callback);
 767   *
 768   * async.auto({
 769   *     get_data: function(callback) {
 770   *         console.log('in get_data');
 771   *         // async code to get some data
 772   *         callback(null, 'data', 'converted to array');
 773   *     },
 774   *     make_folder: function(callback) {
 775   *         console.log('in make_folder');
 776   *         // async code to create a directory to store a file in
 777   *         // this is run at the same time as getting the data
 778   *         callback(null, 'folder');
 779   *     },
 780   *     write_file: ['get_data', 'make_folder', function(results, callback) {
 781   *         console.log('in write_file', JSON.stringify(results));
 782   *         // once there is some data and the directory exists,
 783   *         // write the data to a file in the directory
 784   *         callback(null, 'filename');
 785   *     }],
 786   *     email_link: ['write_file', function(results, callback) {
 787   *         console.log('in email_link', JSON.stringify(results));
 788   *         // once the file is written let's email a link to it...
 789   *         // results.write_file contains the filename returned by write_file.
 790   *         callback(null, {'file':results.write_file, 'email':'user@example.com'});
 791   *     }]
 792   * }, function(err, results) {
 793   *     console.log('err = ', err);
 794   *     console.log('results = ', results);
 795   * });
 796   */
 797  function auto(tasks, concurrency, callback) {
 798      if (typeof concurrency !== 'number') {
 799          // concurrency is optional, shift the args.
 800          callback = concurrency;
 801          concurrency = null;
 802      }
 803      callback = once(callback || promiseCallback());
 804      var numTasks = Object.keys(tasks).length;
 805      if (!numTasks) {
 806          return callback(null);
 807      }
 808      if (!concurrency) {
 809          concurrency = numTasks;
 810      }
 811  
 812      var results = {};
 813      var runningTasks = 0;
 814      var canceled = false;
 815      var hasError = false;
 816  
 817      var listeners = Object.create(null);
 818  
 819      var readyTasks = [];
 820  
 821      // for cycle detection:
 822      var readyToCheck = []; // tasks that have been identified as reachable
 823      // without the possibility of returning to an ancestor task
 824      var uncheckedDependencies = {};
 825  
 826      Object.keys(tasks).forEach(key => {
 827          var task = tasks[key];
 828          if (!Array.isArray(task)) {
 829              // no dependencies
 830              enqueueTask(key, [task]);
 831              readyToCheck.push(key);
 832              return;
 833          }
 834  
 835          var dependencies = task.slice(0, task.length - 1);
 836          var remainingDependencies = dependencies.length;
 837          if (remainingDependencies === 0) {
 838              enqueueTask(key, task);
 839              readyToCheck.push(key);
 840              return;
 841          }
 842          uncheckedDependencies[key] = remainingDependencies;
 843  
 844          dependencies.forEach(dependencyName => {
 845              if (!tasks[dependencyName]) {
 846                  throw new Error('async.auto task `' + key +
 847                      '` has a non-existent dependency `' +
 848                      dependencyName + '` in ' +
 849                      dependencies.join(', '));
 850              }
 851              addListener(dependencyName, () => {
 852                  remainingDependencies--;
 853                  if (remainingDependencies === 0) {
 854                      enqueueTask(key, task);
 855                  }
 856              });
 857          });
 858      });
 859  
 860      checkForDeadlocks();
 861      processQueue();
 862  
 863      function enqueueTask(key, task) {
 864          readyTasks.push(() => runTask(key, task));
 865      }
 866  
 867      function processQueue() {
 868          if (canceled) return
 869          if (readyTasks.length === 0 && runningTasks === 0) {
 870              return callback(null, results);
 871          }
 872          while(readyTasks.length && runningTasks < concurrency) {
 873              var run = readyTasks.shift();
 874              run();
 875          }
 876  
 877      }
 878  
 879      function addListener(taskName, fn) {
 880          var taskListeners = listeners[taskName];
 881          if (!taskListeners) {
 882              taskListeners = listeners[taskName] = [];
 883          }
 884  
 885          taskListeners.push(fn);
 886      }
 887  
 888      function taskComplete(taskName) {
 889          var taskListeners = listeners[taskName] || [];
 890          taskListeners.forEach(fn => fn());
 891          processQueue();
 892      }
 893  
 894  
 895      function runTask(key, task) {
 896          if (hasError) return;
 897  
 898          var taskCallback = onlyOnce((err, ...result) => {
 899              runningTasks--;
 900              if (err === false) {
 901                  canceled = true;
 902                  return
 903              }
 904              if (result.length < 2) {
 905                  [result] = result;
 906              }
 907              if (err) {
 908                  var safeResults = {};
 909                  Object.keys(results).forEach(rkey => {
 910                      safeResults[rkey] = results[rkey];
 911                  });
 912                  safeResults[key] = result;
 913                  hasError = true;
 914                  listeners = Object.create(null);
 915                  if (canceled) return
 916                  callback(err, safeResults);
 917              } else {
 918                  results[key] = result;
 919                  taskComplete(key);
 920              }
 921          });
 922  
 923          runningTasks++;
 924          var taskFn = wrapAsync(task[task.length - 1]);
 925          if (task.length > 1) {
 926              taskFn(results, taskCallback);
 927          } else {
 928              taskFn(taskCallback);
 929          }
 930      }
 931  
 932      function checkForDeadlocks() {
 933          // Kahn's algorithm
 934          // https://en.wikipedia.org/wiki/Topological_sorting#Kahn.27s_algorithm
 935          // http://connalle.blogspot.com/2013/10/topological-sortingkahn-algorithm.html
 936          var currentTask;
 937          var counter = 0;
 938          while (readyToCheck.length) {
 939              currentTask = readyToCheck.pop();
 940              counter++;
 941              getDependents(currentTask).forEach(dependent => {
 942                  if (--uncheckedDependencies[dependent] === 0) {
 943                      readyToCheck.push(dependent);
 944                  }
 945              });
 946          }
 947  
 948          if (counter !== numTasks) {
 949              throw new Error(
 950                  'async.auto cannot execute tasks due to a recursive dependency'
 951              );
 952          }
 953      }
 954  
 955      function getDependents(taskName) {
 956          var result = [];
 957          Object.keys(tasks).forEach(key => {
 958              const task = tasks[key];
 959              if (Array.isArray(task) && task.indexOf(taskName) >= 0) {
 960                  result.push(key);
 961              }
 962          });
 963          return result;
 964      }
 965  
 966      return callback[PROMISE_SYMBOL]
 967  }
 968  
 969  var FN_ARGS = /^(?:async\s+)?(?:function)?\s*\w*\s*\(\s*([^)]+)\s*\)(?:\s*{)/;
 970  var ARROW_FN_ARGS = /^(?:async\s+)?\(?\s*([^)=]+)\s*\)?(?:\s*=>)/;
 971  var FN_ARG_SPLIT = /,/;
 972  var FN_ARG = /(=.+)?(\s*)$/;
 973  var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
 974  
 975  function parseParams(func) {
 976      const src = func.toString().replace(STRIP_COMMENTS, '');
 977      let match = src.match(FN_ARGS);
 978      if (!match) {
 979          match = src.match(ARROW_FN_ARGS);
 980      }
 981      if (!match) throw new Error('could not parse args in autoInject\nSource:\n' + src)
 982      let [, args] = match;
 983      return args
 984          .replace(/\s/g, '')
 985          .split(FN_ARG_SPLIT)
 986          .map((arg) => arg.replace(FN_ARG, '').trim());
 987  }
 988  
 989  /**
 990   * A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent
 991   * tasks are specified as parameters to the function, after the usual callback
 992   * parameter, with the parameter names matching the names of the tasks it
 993   * depends on. This can provide even more readable task graphs which can be
 994   * easier to maintain.
 995   *
 996   * If a final callback is specified, the task results are similarly injected,
 997   * specified as named parameters after the initial error parameter.
 998   *
 999   * The autoInject function is purely syntactic sugar and its semantics are
1000   * otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}.
1001   *
1002   * @name autoInject
1003   * @static
1004   * @memberOf module:ControlFlow
1005   * @method
1006   * @see [async.auto]{@link module:ControlFlow.auto}
1007   * @category Control Flow
1008   * @param {Object} tasks - An object, each of whose properties is an {@link AsyncFunction} of
1009   * the form 'func([dependencies...], callback). The object's key of a property
1010   * serves as the name of the task defined by that property, i.e. can be used
1011   * when specifying requirements for other tasks.
1012   * * The `callback` parameter is a `callback(err, result)` which must be called
1013   *   when finished, passing an `error` (which can be `null`) and the result of
1014   *   the function's execution. The remaining parameters name other tasks on
1015   *   which the task is dependent, and the results from those tasks are the
1016   *   arguments of those parameters.
1017   * @param {Function} [callback] - An optional callback which is called when all
1018   * the tasks have been completed. It receives the `err` argument if any `tasks`
1019   * pass an error to their callback, and a `results` object with any completed
1020   * task results, similar to `auto`.
1021   * @returns {Promise} a promise, if no callback is passed
1022   * @example
1023   *
1024   * //  The example from `auto` can be rewritten as follows:
1025   * async.autoInject({
1026   *     get_data: function(callback) {
1027   *         // async code to get some data
1028   *         callback(null, 'data', 'converted to array');
1029   *     },
1030   *     make_folder: function(callback) {
1031   *         // async code to create a directory to store a file in
1032   *         // this is run at the same time as getting the data
1033   *         callback(null, 'folder');
1034   *     },
1035   *     write_file: function(get_data, make_folder, callback) {
1036   *         // once there is some data and the directory exists,
1037   *         // write the data to a file in the directory
1038   *         callback(null, 'filename');
1039   *     },
1040   *     email_link: function(write_file, callback) {
1041   *         // once the file is written let's email a link to it...
1042   *         // write_file contains the filename returned by write_file.
1043   *         callback(null, {'file':write_file, 'email':'user@example.com'});
1044   *     }
1045   * }, function(err, results) {
1046   *     console.log('err = ', err);
1047   *     console.log('email_link = ', results.email_link);
1048   * });
1049   *
1050   * // If you are using a JS minifier that mangles parameter names, `autoInject`
1051   * // will not work with plain functions, since the parameter names will be
1052   * // collapsed to a single letter identifier.  To work around this, you can
1053   * // explicitly specify the names of the parameters your task function needs
1054   * // in an array, similar to Angular.js dependency injection.
1055   *
1056   * // This still has an advantage over plain `auto`, since the results a task
1057   * // depends on are still spread into arguments.
1058   * async.autoInject({
1059   *     //...
1060   *     write_file: ['get_data', 'make_folder', function(get_data, make_folder, callback) {
1061   *         callback(null, 'filename');
1062   *     }],
1063   *     email_link: ['write_file', function(write_file, callback) {
1064   *         callback(null, {'file':write_file, 'email':'user@example.com'});
1065   *     }]
1066   *     //...
1067   * }, function(err, results) {
1068   *     console.log('err = ', err);
1069   *     console.log('email_link = ', results.email_link);
1070   * });
1071   */
1072  function autoInject(tasks, callback) {
1073      var newTasks = {};
1074  
1075      Object.keys(tasks).forEach(key => {
1076          var taskFn = tasks[key];
1077          var params;
1078          var fnIsAsync = isAsync(taskFn);
1079          var hasNoDeps =
1080              (!fnIsAsync && taskFn.length === 1) ||
1081              (fnIsAsync && taskFn.length === 0);
1082  
1083          if (Array.isArray(taskFn)) {
1084              params = [...taskFn];
1085              taskFn = params.pop();
1086  
1087              newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn);
1088          } else if (hasNoDeps) {
1089              // no dependencies, use the function as-is
1090              newTasks[key] = taskFn;
1091          } else {
1092              params = parseParams(taskFn);
1093              if ((taskFn.length === 0 && !fnIsAsync) && params.length === 0) {
1094                  throw new Error("autoInject task functions require explicit parameters.");
1095              }
1096  
1097              // remove callback param
1098              if (!fnIsAsync) params.pop();
1099  
1100              newTasks[key] = params.concat(newTask);
1101          }
1102  
1103          function newTask(results, taskCb) {
1104              var newArgs = params.map(name => results[name]);
1105              newArgs.push(taskCb);
1106              wrapAsync(taskFn)(...newArgs);
1107          }
1108      });
1109  
1110      return auto(newTasks, callback);
1111  }
1112  
1113  // Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
1114  // used for queues. This implementation assumes that the node provided by the user can be modified
1115  // to adjust the next and last properties. We implement only the minimal functionality
1116  // for queue support.
1117  class DLL {
1118      constructor() {
1119          this.head = this.tail = null;
1120          this.length = 0;
1121      }
1122  
1123      removeLink(node) {
1124          if (node.prev) node.prev.next = node.next;
1125          else this.head = node.next;
1126          if (node.next) node.next.prev = node.prev;
1127          else this.tail = node.prev;
1128  
1129          node.prev = node.next = null;
1130          this.length -= 1;
1131          return node;
1132      }
1133  
1134      empty () {
1135          while(this.head) this.shift();
1136          return this;
1137      }
1138  
1139      insertAfter(node, newNode) {
1140          newNode.prev = node;
1141          newNode.next = node.next;
1142          if (node.next) node.next.prev = newNode;
1143          else this.tail = newNode;
1144          node.next = newNode;
1145          this.length += 1;
1146      }
1147  
1148      insertBefore(node, newNode) {
1149          newNode.prev = node.prev;
1150          newNode.next = node;
1151          if (node.prev) node.prev.next = newNode;
1152          else this.head = newNode;
1153          node.prev = newNode;
1154          this.length += 1;
1155      }
1156  
1157      unshift(node) {
1158          if (this.head) this.insertBefore(this.head, node);
1159          else setInitial(this, node);
1160      }
1161  
1162      push(node) {
1163          if (this.tail) this.insertAfter(this.tail, node);
1164          else setInitial(this, node);
1165      }
1166  
1167      shift() {
1168          return this.head && this.removeLink(this.head);
1169      }
1170  
1171      pop() {
1172          return this.tail && this.removeLink(this.tail);
1173      }
1174  
1175      toArray() {
1176          return [...this]
1177      }
1178  
1179      *[Symbol.iterator] () {
1180          var cur = this.head;
1181          while (cur) {
1182              yield cur.data;
1183              cur = cur.next;
1184          }
1185      }
1186  
1187      remove (testFn) {
1188          var curr = this.head;
1189          while(curr) {
1190              var {next} = curr;
1191              if (testFn(curr)) {
1192                  this.removeLink(curr);
1193              }
1194              curr = next;
1195          }
1196          return this;
1197      }
1198  }
1199  
1200  function setInitial(dll, node) {
1201      dll.length = 1;
1202      dll.head = dll.tail = node;
1203  }
1204  
1205  function queue(worker, concurrency, payload) {
1206      if (concurrency == null) {
1207          concurrency = 1;
1208      }
1209      else if(concurrency === 0) {
1210          throw new RangeError('Concurrency must not be zero');
1211      }
1212  
1213      var _worker = wrapAsync(worker);
1214      var numRunning = 0;
1215      var workersList = [];
1216      const events = {
1217          error: [],
1218          drain: [],
1219          saturated: [],
1220          unsaturated: [],
1221          empty: []
1222      };
1223  
1224      function on (event, handler) {
1225          events[event].push(handler);
1226      }
1227  
1228      function once (event, handler) {
1229          const handleAndRemove = (...args) => {
1230              off(event, handleAndRemove);
1231              handler(...args);
1232          };
1233          events[event].push(handleAndRemove);
1234      }
1235  
1236      function off (event, handler) {
1237          if (!event) return Object.keys(events).forEach(ev => events[ev] = [])
1238          if (!handler) return events[event] = []
1239          events[event] = events[event].filter(ev => ev !== handler);
1240      }
1241  
1242      function trigger (event, ...args) {
1243          events[event].forEach(handler => handler(...args));
1244      }
1245  
1246      var processingScheduled = false;
1247      function _insert(data, insertAtFront, rejectOnError, callback) {
1248          if (callback != null && typeof callback !== 'function') {
1249              throw new Error('task callback must be a function');
1250          }
1251          q.started = true;
1252  
1253          var res, rej;
1254          function promiseCallback (err, ...args) {
1255              // we don't care about the error, let the global error handler
1256              // deal with it
1257              if (err) return rejectOnError ? rej(err) : res()
1258              if (args.length <= 1) return res(args[0])
1259              res(args);
1260          }
1261  
1262          var item = {
1263              data,
1264              callback: rejectOnError ?
1265                  promiseCallback :
1266                  (callback || promiseCallback)
1267          };
1268  
1269          if (insertAtFront) {
1270              q._tasks.unshift(item);
1271          } else {
1272              q._tasks.push(item);
1273          }
1274  
1275          if (!processingScheduled) {
1276              processingScheduled = true;
1277              setImmediate$1(() => {
1278                  processingScheduled = false;
1279                  q.process();
1280              });
1281          }
1282  
1283          if (rejectOnError || !callback) {
1284              return new Promise((resolve, reject) => {
1285                  res = resolve;
1286                  rej = reject;
1287              })
1288          }
1289      }
1290  
1291      function _createCB(tasks) {
1292          return function (err, ...args) {
1293              numRunning -= 1;
1294  
1295              for (var i = 0, l = tasks.length; i < l; i++) {
1296                  var task = tasks[i];
1297  
1298                  var index = workersList.indexOf(task);
1299                  if (index === 0) {
1300                      workersList.shift();
1301                  } else if (index > 0) {
1302                      workersList.splice(index, 1);
1303                  }
1304  
1305                  task.callback(err, ...args);
1306  
1307                  if (err != null) {
1308                      trigger('error', err, task.data);
1309                  }
1310              }
1311  
1312              if (numRunning <= (q.concurrency - q.buffer) ) {
1313                  trigger('unsaturated');
1314              }
1315  
1316              if (q.idle()) {
1317                  trigger('drain');
1318              }
1319              q.process();
1320          };
1321      }
1322  
1323      function _maybeDrain(data) {
1324          if (data.length === 0 && q.idle()) {
1325              // call drain immediately if there are no tasks
1326              setImmediate$1(() => trigger('drain'));
1327              return true
1328          }
1329          return false
1330      }
1331  
1332      const eventMethod = (name) => (handler) => {
1333          if (!handler) {
1334              return new Promise((resolve, reject) => {
1335                  once(name, (err, data) => {
1336                      if (err) return reject(err)
1337                      resolve(data);
1338                  });
1339              })
1340          }
1341          off(name);
1342          on(name, handler);
1343  
1344      };
1345  
1346      var isProcessing = false;
1347      var q = {
1348          _tasks: new DLL(),
1349          *[Symbol.iterator] () {
1350              yield* q._tasks[Symbol.iterator]();
1351          },
1352          concurrency,
1353          payload,
1354          buffer: concurrency / 4,
1355          started: false,
1356          paused: false,
1357          push (data, callback) {
1358              if (Array.isArray(data)) {
1359                  if (_maybeDrain(data)) return
1360                  return data.map(datum => _insert(datum, false, false, callback))
1361              }
1362              return _insert(data, false, false, callback);
1363          },
1364          pushAsync (data, callback) {
1365              if (Array.isArray(data)) {
1366                  if (_maybeDrain(data)) return
1367                  return data.map(datum => _insert(datum, false, true, callback))
1368              }
1369              return _insert(data, false, true, callback);
1370          },
1371          kill () {
1372              off();
1373              q._tasks.empty();
1374          },
1375          unshift (data, callback) {
1376              if (Array.isArray(data)) {
1377                  if (_maybeDrain(data)) return
1378                  return data.map(datum => _insert(datum, true, false, callback))
1379              }
1380              return _insert(data, true, false, callback);
1381          },
1382          unshiftAsync (data, callback) {
1383              if (Array.isArray(data)) {
1384                  if (_maybeDrain(data)) return
1385                  return data.map(datum => _insert(datum, true, true, callback))
1386              }
1387              return _insert(data, true, true, callback);
1388          },
1389          remove (testFn) {
1390              q._tasks.remove(testFn);
1391          },
1392          process () {
1393              // Avoid trying to start too many processing operations. This can occur
1394              // when callbacks resolve synchronously (#1267).
1395              if (isProcessing) {
1396                  return;
1397              }
1398              isProcessing = true;
1399              while(!q.paused && numRunning < q.concurrency && q._tasks.length){
1400                  var tasks = [], data = [];
1401                  var l = q._tasks.length;
1402                  if (q.payload) l = Math.min(l, q.payload);
1403                  for (var i = 0; i < l; i++) {
1404                      var node = q._tasks.shift();
1405                      tasks.push(node);
1406                      workersList.push(node);
1407                      data.push(node.data);
1408                  }
1409  
1410                  numRunning += 1;
1411  
1412                  if (q._tasks.length === 0) {
1413                      trigger('empty');
1414                  }
1415  
1416                  if (numRunning === q.concurrency) {
1417                      trigger('saturated');
1418                  }
1419  
1420                  var cb = onlyOnce(_createCB(tasks));
1421                  _worker(data, cb);
1422              }
1423              isProcessing = false;
1424          },
1425          length () {
1426              return q._tasks.length;
1427          },
1428          running () {
1429              return numRunning;
1430          },
1431          workersList () {
1432              return workersList;
1433          },
1434          idle() {
1435              return q._tasks.length + numRunning === 0;
1436          },
1437          pause () {
1438              q.paused = true;
1439          },
1440          resume () {
1441              if (q.paused === false) { return; }
1442              q.paused = false;
1443              setImmediate$1(q.process);
1444          }
1445      };
1446      // define these as fixed properties, so people get useful errors when updating
1447      Object.defineProperties(q, {
1448          saturated: {
1449              writable: false,
1450              value: eventMethod('saturated')
1451          },
1452          unsaturated: {
1453              writable: false,
1454              value: eventMethod('unsaturated')
1455          },
1456          empty: {
1457              writable: false,
1458              value: eventMethod('empty')
1459          },
1460          drain: {
1461              writable: false,
1462              value: eventMethod('drain')
1463          },
1464          error: {
1465              writable: false,
1466              value: eventMethod('error')
1467          },
1468      });
1469      return q;
1470  }
1471  
1472  /**
1473   * Creates a `cargo` object with the specified payload. Tasks added to the
1474   * cargo will be processed altogether (up to the `payload` limit). If the
1475   * `worker` is in progress, the task is queued until it becomes available. Once
1476   * the `worker` has completed some tasks, each callback of those tasks is
1477   * called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
1478   * for how `cargo` and `queue` work.
1479   *
1480   * While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
1481   * at a time, cargo passes an array of tasks to a single worker, repeating
1482   * when the worker is finished.
1483   *
1484   * @name cargo
1485   * @static
1486   * @memberOf module:ControlFlow
1487   * @method
1488   * @see [async.queue]{@link module:ControlFlow.queue}
1489   * @category Control Flow
1490   * @param {AsyncFunction} worker - An asynchronous function for processing an array
1491   * of queued tasks. Invoked with `(tasks, callback)`.
1492   * @param {number} [payload=Infinity] - An optional `integer` for determining
1493   * how many tasks should be processed per round; if omitted, the default is
1494   * unlimited.
1495   * @returns {module:ControlFlow.QueueObject} A cargo object to manage the tasks. Callbacks can
1496   * attached as certain properties to listen for specific events during the
1497   * lifecycle of the cargo and inner queue.
1498   * @example
1499   *
1500   * // create a cargo object with payload 2
1501   * var cargo = async.cargo(function(tasks, callback) {
1502   *     for (var i=0; i<tasks.length; i++) {
1503   *         console.log('hello ' + tasks[i].name);
1504   *     }
1505   *     callback();
1506   * }, 2);
1507   *
1508   * // add some items
1509   * cargo.push({name: 'foo'}, function(err) {
1510   *     console.log('finished processing foo');
1511   * });
1512   * cargo.push({name: 'bar'}, function(err) {
1513   *     console.log('finished processing bar');
1514   * });
1515   * await cargo.push({name: 'baz'});
1516   * console.log('finished processing baz');
1517   */
1518  function cargo(worker, payload) {
1519      return queue(worker, 1, payload);
1520  }
1521  
1522  /**
1523   * Creates a `cargoQueue` object with the specified payload. Tasks added to the
1524   * cargoQueue will be processed together (up to the `payload` limit) in `concurrency` parallel workers.
1525   * If the all `workers` are in progress, the task is queued until one becomes available. Once
1526   * a `worker` has completed some tasks, each callback of those tasks is
1527   * called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
1528   * for how `cargo` and `queue` work.
1529   *
1530   * While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
1531   * at a time, and [`cargo`]{@link module:ControlFlow.cargo} passes an array of tasks to a single worker,
1532   * the cargoQueue passes an array of tasks to multiple parallel workers.
1533   *
1534   * @name cargoQueue
1535   * @static
1536   * @memberOf module:ControlFlow
1537   * @method
1538   * @see [async.queue]{@link module:ControlFlow.queue}
1539   * @see [async.cargo]{@link module:ControlFLow.cargo}
1540   * @category Control Flow
1541   * @param {AsyncFunction} worker - An asynchronous function for processing an array
1542   * of queued tasks. Invoked with `(tasks, callback)`.
1543   * @param {number} [concurrency=1] - An `integer` for determining how many
1544   * `worker` functions should be run in parallel.  If omitted, the concurrency
1545   * defaults to `1`.  If the concurrency is `0`, an error is thrown.
1546   * @param {number} [payload=Infinity] - An optional `integer` for determining
1547   * how many tasks should be processed per round; if omitted, the default is
1548   * unlimited.
1549   * @returns {module:ControlFlow.QueueObject} A cargoQueue object to manage the tasks. Callbacks can
1550   * attached as certain properties to listen for specific events during the
1551   * lifecycle of the cargoQueue and inner queue.
1552   * @example
1553   *
1554   * // create a cargoQueue object with payload 2 and concurrency 2
1555   * var cargoQueue = async.cargoQueue(function(tasks, callback) {
1556   *     for (var i=0; i<tasks.length; i++) {
1557   *         console.log('hello ' + tasks[i].name);
1558   *     }
1559   *     callback();
1560   * }, 2, 2);
1561   *
1562   * // add some items
1563   * cargoQueue.push({name: 'foo'}, function(err) {
1564   *     console.log('finished processing foo');
1565   * });
1566   * cargoQueue.push({name: 'bar'}, function(err) {
1567   *     console.log('finished processing bar');
1568   * });
1569   * cargoQueue.push({name: 'baz'}, function(err) {
1570   *     console.log('finished processing baz');
1571   * });
1572   * cargoQueue.push({name: 'boo'}, function(err) {
1573   *     console.log('finished processing boo');
1574   * });
1575   */
1576  function cargo$1(worker, concurrency, payload) {
1577      return queue(worker, concurrency, payload);
1578  }
1579  
1580  /**
1581   * Reduces `coll` into a single value using an async `iteratee` to return each
1582   * successive step. `memo` is the initial state of the reduction. This function
1583   * only operates in series.
1584   *
1585   * For performance reasons, it may make sense to split a call to this function
1586   * into a parallel map, and then use the normal `Array.prototype.reduce` on the
1587   * results. This function is for situations where each step in the reduction
1588   * needs to be async; if you can get the data before reducing it, then it's
1589   * probably a good idea to do so.
1590   *
1591   * @name reduce
1592   * @static
1593   * @memberOf module:Collections
1594   * @method
1595   * @alias inject
1596   * @alias foldl
1597   * @category Collection
1598   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1599   * @param {*} memo - The initial state of the reduction.
1600   * @param {AsyncFunction} iteratee - A function applied to each item in the
1601   * array to produce the next step in the reduction.
1602   * The `iteratee` should complete with the next state of the reduction.
1603   * If the iteratee complete with an error, the reduction is stopped and the
1604   * main `callback` is immediately called with the error.
1605   * Invoked with (memo, item, callback).
1606   * @param {Function} [callback] - A callback which is called after all the
1607   * `iteratee` functions have finished. Result is the reduced value. Invoked with
1608   * (err, result).
1609   * @returns {Promise} a promise, if no callback is passed
1610   * @example
1611   *
1612   * async.reduce([1,2,3], 0, function(memo, item, callback) {
1613   *     // pointless async:
1614   *     process.nextTick(function() {
1615   *         callback(null, memo + item)
1616   *     });
1617   * }, function(err, result) {
1618   *     // result is now equal to the last value of memo, which is 6
1619   * });
1620   */
1621  function reduce(coll, memo, iteratee, callback) {
1622      callback = once(callback);
1623      var _iteratee = wrapAsync(iteratee);
1624      return eachOfSeries$1(coll, (x, i, iterCb) => {
1625          _iteratee(memo, x, (err, v) => {
1626              memo = v;
1627              iterCb(err);
1628          });
1629      }, err => callback(err, memo));
1630  }
1631  var reduce$1 = awaitify(reduce, 4);
1632  
1633  /**
1634   * Version of the compose function that is more natural to read. Each function
1635   * consumes the return value of the previous function. It is the equivalent of
1636   * [compose]{@link module:ControlFlow.compose} with the arguments reversed.
1637   *
1638   * Each function is executed with the `this` binding of the composed function.
1639   *
1640   * @name seq
1641   * @static
1642   * @memberOf module:ControlFlow
1643   * @method
1644   * @see [async.compose]{@link module:ControlFlow.compose}
1645   * @category Control Flow
1646   * @param {...AsyncFunction} functions - the asynchronous functions to compose
1647   * @returns {Function} a function that composes the `functions` in order
1648   * @example
1649   *
1650   * // Requires lodash (or underscore), express3 and dresende's orm2.
1651   * // Part of an app, that fetches cats of the logged user.
1652   * // This example uses `seq` function to avoid overnesting and error
1653   * // handling clutter.
1654   * app.get('/cats', function(request, response) {
1655   *     var User = request.models.User;
1656   *     async.seq(
1657   *         _.bind(User.get, User),  // 'User.get' has signature (id, callback(err, data))
1658   *         function(user, fn) {
1659   *             user.getCats(fn);      // 'getCats' has signature (callback(err, data))
1660   *         }
1661   *     )(req.session.user_id, function (err, cats) {
1662   *         if (err) {
1663   *             console.error(err);
1664   *             response.json({ status: 'error', message: err.message });
1665   *         } else {
1666   *             response.json({ status: 'ok', message: 'Cats found', data: cats });
1667   *         }
1668   *     });
1669   * });
1670   */
1671  function seq(...functions) {
1672      var _functions = functions.map(wrapAsync);
1673      return function (...args) {
1674          var that = this;
1675  
1676          var cb = args[args.length - 1];
1677          if (typeof cb == 'function') {
1678              args.pop();
1679          } else {
1680              cb = promiseCallback();
1681          }
1682  
1683          reduce$1(_functions, args, (newargs, fn, iterCb) => {
1684              fn.apply(that, newargs.concat((err, ...nextargs) => {
1685                  iterCb(err, nextargs);
1686              }));
1687          },
1688          (err, results) => cb(err, ...results));
1689  
1690          return cb[PROMISE_SYMBOL]
1691      };
1692  }
1693  
1694  /**
1695   * Creates a function which is a composition of the passed asynchronous
1696   * functions. Each function consumes the return value of the function that
1697   * follows. Composing functions `f()`, `g()`, and `h()` would produce the result
1698   * of `f(g(h()))`, only this version uses callbacks to obtain the return values.
1699   *
1700   * If the last argument to the composed function is not a function, a promise
1701   * is returned when you call it.
1702   *
1703   * Each function is executed with the `this` binding of the composed function.
1704   *
1705   * @name compose
1706   * @static
1707   * @memberOf module:ControlFlow
1708   * @method
1709   * @category Control Flow
1710   * @param {...AsyncFunction} functions - the asynchronous functions to compose
1711   * @returns {Function} an asynchronous function that is the composed
1712   * asynchronous `functions`
1713   * @example
1714   *
1715   * function add1(n, callback) {
1716   *     setTimeout(function () {
1717   *         callback(null, n + 1);
1718   *     }, 10);
1719   * }
1720   *
1721   * function mul3(n, callback) {
1722   *     setTimeout(function () {
1723   *         callback(null, n * 3);
1724   *     }, 10);
1725   * }
1726   *
1727   * var add1mul3 = async.compose(mul3, add1);
1728   * add1mul3(4, function (err, result) {
1729   *     // result now equals 15
1730   * });
1731   */
1732  function compose(...args) {
1733      return seq(...args.reverse());
1734  }
1735  
1736  /**
1737   * The same as [`map`]{@link module:Collections.map} but runs a maximum of `limit` async operations at a time.
1738   *
1739   * @name mapLimit
1740   * @static
1741   * @memberOf module:Collections
1742   * @method
1743   * @see [async.map]{@link module:Collections.map}
1744   * @category Collection
1745   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1746   * @param {number} limit - The maximum number of async operations at a time.
1747   * @param {AsyncFunction} iteratee - An async function to apply to each item in
1748   * `coll`.
1749   * The iteratee should complete with the transformed item.
1750   * Invoked with (item, callback).
1751   * @param {Function} [callback] - A callback which is called when all `iteratee`
1752   * functions have finished, or an error occurs. Results is an array of the
1753   * transformed items from the `coll`. Invoked with (err, results).
1754   * @returns {Promise} a promise, if no callback is passed
1755   */
1756  function mapLimit (coll, limit, iteratee, callback) {
1757      return _asyncMap(eachOfLimit(limit), coll, iteratee, callback)
1758  }
1759  var mapLimit$1 = awaitify(mapLimit, 4);
1760  
1761  /**
1762   * The same as [`concat`]{@link module:Collections.concat} but runs a maximum of `limit` async operations at a time.
1763   *
1764   * @name concatLimit
1765   * @static
1766   * @memberOf module:Collections
1767   * @method
1768   * @see [async.concat]{@link module:Collections.concat}
1769   * @category Collection
1770   * @alias flatMapLimit
1771   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1772   * @param {number} limit - The maximum number of async operations at a time.
1773   * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
1774   * which should use an array as its result. Invoked with (item, callback).
1775   * @param {Function} [callback] - A callback which is called after all the
1776   * `iteratee` functions have finished, or an error occurs. Results is an array
1777   * containing the concatenated results of the `iteratee` function. Invoked with
1778   * (err, results).
1779   * @returns A Promise, if no callback is passed
1780   */
1781  function concatLimit(coll, limit, iteratee, callback) {
1782      var _iteratee = wrapAsync(iteratee);
1783      return mapLimit$1(coll, limit, (val, iterCb) => {
1784          _iteratee(val, (err, ...args) => {
1785              if (err) return iterCb(err);
1786              return iterCb(err, args);
1787          });
1788      }, (err, mapResults) => {
1789          var result = [];
1790          for (var i = 0; i < mapResults.length; i++) {
1791              if (mapResults[i]) {
1792                  result = result.concat(...mapResults[i]);
1793              }
1794          }
1795  
1796          return callback(err, result);
1797      });
1798  }
1799  var concatLimit$1 = awaitify(concatLimit, 4);
1800  
1801  /**
1802   * Applies `iteratee` to each item in `coll`, concatenating the results. Returns
1803   * the concatenated list. The `iteratee`s are called in parallel, and the
1804   * results are concatenated as they return. The results array will be returned in
1805   * the original order of `coll` passed to the `iteratee` function.
1806   *
1807   * @name concat
1808   * @static
1809   * @memberOf module:Collections
1810   * @method
1811   * @category Collection
1812   * @alias flatMap
1813   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1814   * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
1815   * which should use an array as its result. Invoked with (item, callback).
1816   * @param {Function} [callback] - A callback which is called after all the
1817   * `iteratee` functions have finished, or an error occurs. Results is an array
1818   * containing the concatenated results of the `iteratee` function. Invoked with
1819   * (err, results).
1820   * @returns A Promise, if no callback is passed
1821   * @example
1822   *
1823   * async.concat(['dir1','dir2','dir3'], fs.readdir, function(err, files) {
1824   *     // files is now a list of filenames that exist in the 3 directories
1825   * });
1826   */
1827  function concat(coll, iteratee, callback) {
1828      return concatLimit$1(coll, Infinity, iteratee, callback)
1829  }
1830  var concat$1 = awaitify(concat, 3);
1831  
1832  /**
1833   * The same as [`concat`]{@link module:Collections.concat} but runs only a single async operation at a time.
1834   *
1835   * @name concatSeries
1836   * @static
1837   * @memberOf module:Collections
1838   * @method
1839   * @see [async.concat]{@link module:Collections.concat}
1840   * @category Collection
1841   * @alias flatMapSeries
1842   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1843   * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`.
1844   * The iteratee should complete with an array an array of results.
1845   * Invoked with (item, callback).
1846   * @param {Function} [callback] - A callback which is called after all the
1847   * `iteratee` functions have finished, or an error occurs. Results is an array
1848   * containing the concatenated results of the `iteratee` function. Invoked with
1849   * (err, results).
1850   * @returns A Promise, if no callback is passed
1851   */
1852  function concatSeries(coll, iteratee, callback) {
1853      return concatLimit$1(coll, 1, iteratee, callback)
1854  }
1855  var concatSeries$1 = awaitify(concatSeries, 3);
1856  
1857  /**
1858   * Returns a function that when called, calls-back with the values provided.
1859   * Useful as the first function in a [`waterfall`]{@link module:ControlFlow.waterfall}, or for plugging values in to
1860   * [`auto`]{@link module:ControlFlow.auto}.
1861   *
1862   * @name constant
1863   * @static
1864   * @memberOf module:Utils
1865   * @method
1866   * @category Util
1867   * @param {...*} arguments... - Any number of arguments to automatically invoke
1868   * callback with.
1869   * @returns {AsyncFunction} Returns a function that when invoked, automatically
1870   * invokes the callback with the previous given arguments.
1871   * @example
1872   *
1873   * async.waterfall([
1874   *     async.constant(42),
1875   *     function (value, next) {
1876   *         // value === 42
1877   *     },
1878   *     //...
1879   * ], callback);
1880   *
1881   * async.waterfall([
1882   *     async.constant(filename, "utf8"),
1883   *     fs.readFile,
1884   *     function (fileData, next) {
1885   *         //...
1886   *     }
1887   *     //...
1888   * ], callback);
1889   *
1890   * async.auto({
1891   *     hostname: async.constant("https://server.net/"),
1892   *     port: findFreePort,
1893   *     launchServer: ["hostname", "port", function (options, cb) {
1894   *         startServer(options, cb);
1895   *     }],
1896   *     //...
1897   * }, callback);
1898   */
1899  function constant(...args) {
1900      return function (...ignoredArgs/*, callback*/) {
1901          var callback = ignoredArgs.pop();
1902          return callback(null, ...args);
1903      };
1904  }
1905  
1906  function _createTester(check, getResult) {
1907      return (eachfn, arr, _iteratee, cb) => {
1908          var testPassed = false;
1909          var testResult;
1910          const iteratee = wrapAsync(_iteratee);
1911          eachfn(arr, (value, _, callback) => {
1912              iteratee(value, (err, result) => {
1913                  if (err || err === false) return callback(err);
1914  
1915                  if (check(result) && !testResult) {
1916                      testPassed = true;
1917                      testResult = getResult(true, value);
1918                      return callback(null, breakLoop);
1919                  }
1920                  callback();
1921              });
1922          }, err => {
1923              if (err) return cb(err);
1924              cb(null, testPassed ? testResult : getResult(false));
1925          });
1926      };
1927  }
1928  
1929  /**
1930   * Returns the first value in `coll` that passes an async truth test. The
1931   * `iteratee` is applied in parallel, meaning the first iteratee to return
1932   * `true` will fire the detect `callback` with that result. That means the
1933   * result might not be the first item in the original `coll` (in terms of order)
1934   * that passes the test.
1935  
1936   * If order within the original `coll` is important, then look at
1937   * [`detectSeries`]{@link module:Collections.detectSeries}.
1938   *
1939   * @name detect
1940   * @static
1941   * @memberOf module:Collections
1942   * @method
1943   * @alias find
1944   * @category Collections
1945   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1946   * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
1947   * The iteratee must complete with a boolean value as its result.
1948   * Invoked with (item, callback).
1949   * @param {Function} [callback] - A callback which is called as soon as any
1950   * iteratee returns `true`, or after all the `iteratee` functions have finished.
1951   * Result will be the first item in the array that passes the truth test
1952   * (iteratee) or the value `undefined` if none passed. Invoked with
1953   * (err, result).
1954   * @returns A Promise, if no callback is passed
1955   * @example
1956   *
1957   * async.detect(['file1','file2','file3'], function(filePath, callback) {
1958   *     fs.access(filePath, function(err) {
1959   *         callback(null, !err)
1960   *     });
1961   * }, function(err, result) {
1962   *     // result now equals the first file in the list that exists
1963   * });
1964   */
1965  function detect(coll, iteratee, callback) {
1966      return _createTester(bool => bool, (res, item) => item)(eachOf$1, coll, iteratee, callback)
1967  }
1968  var detect$1 = awaitify(detect, 3);
1969  
1970  /**
1971   * The same as [`detect`]{@link module:Collections.detect} but runs a maximum of `limit` async operations at a
1972   * time.
1973   *
1974   * @name detectLimit
1975   * @static
1976   * @memberOf module:Collections
1977   * @method
1978   * @see [async.detect]{@link module:Collections.detect}
1979   * @alias findLimit
1980   * @category Collections
1981   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
1982   * @param {number} limit - The maximum number of async operations at a time.
1983   * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
1984   * The iteratee must complete with a boolean value as its result.
1985   * Invoked with (item, callback).
1986   * @param {Function} [callback] - A callback which is called as soon as any
1987   * iteratee returns `true`, or after all the `iteratee` functions have finished.
1988   * Result will be the first item in the array that passes the truth test
1989   * (iteratee) or the value `undefined` if none passed. Invoked with
1990   * (err, result).
1991   * @returns a Promise if no callback is passed
1992   */
1993  function detectLimit(coll, limit, iteratee, callback) {
1994      return _createTester(bool => bool, (res, item) => item)(eachOfLimit(limit), coll, iteratee, callback)
1995  }
1996  var detectLimit$1 = awaitify(detectLimit, 4);
1997  
1998  /**
1999   * The same as [`detect`]{@link module:Collections.detect} but runs only a single async operation at a time.
2000   *
2001   * @name detectSeries
2002   * @static
2003   * @memberOf module:Collections
2004   * @method
2005   * @see [async.detect]{@link module:Collections.detect}
2006   * @alias findSeries
2007   * @category Collections
2008   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2009   * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
2010   * The iteratee must complete with a boolean value as its result.
2011   * Invoked with (item, callback).
2012   * @param {Function} [callback] - A callback which is called as soon as any
2013   * iteratee returns `true`, or after all the `iteratee` functions have finished.
2014   * Result will be the first item in the array that passes the truth test
2015   * (iteratee) or the value `undefined` if none passed. Invoked with
2016   * (err, result).
2017   * @returns a Promise if no callback is passed
2018   */
2019  function detectSeries(coll, iteratee, callback) {
2020      return _createTester(bool => bool, (res, item) => item)(eachOfLimit(1), coll, iteratee, callback)
2021  }
2022  
2023  var detectSeries$1 = awaitify(detectSeries, 3);
2024  
2025  function consoleFunc(name) {
2026      return (fn, ...args) => wrapAsync(fn)(...args, (err, ...resultArgs) => {
2027          if (typeof console === 'object') {
2028              if (err) {
2029                  if (console.error) {
2030                      console.error(err);
2031                  }
2032              } else if (console[name]) {
2033                  resultArgs.forEach(x => console[name](x));
2034              }
2035          }
2036      })
2037  }
2038  
2039  /**
2040   * Logs the result of an [`async` function]{@link AsyncFunction} to the
2041   * `console` using `console.dir` to display the properties of the resulting object.
2042   * Only works in Node.js or in browsers that support `console.dir` and
2043   * `console.error` (such as FF and Chrome).
2044   * If multiple arguments are returned from the async function,
2045   * `console.dir` is called on each argument in order.
2046   *
2047   * @name dir
2048   * @static
2049   * @memberOf module:Utils
2050   * @method
2051   * @category Util
2052   * @param {AsyncFunction} function - The function you want to eventually apply
2053   * all arguments to.
2054   * @param {...*} arguments... - Any number of arguments to apply to the function.
2055   * @example
2056   *
2057   * // in a module
2058   * var hello = function(name, callback) {
2059   *     setTimeout(function() {
2060   *         callback(null, {hello: name});
2061   *     }, 1000);
2062   * };
2063   *
2064   * // in the node repl
2065   * node> async.dir(hello, 'world');
2066   * {hello: 'world'}
2067   */
2068  var dir = consoleFunc('dir');
2069  
2070  /**
2071   * The post-check version of [`whilst`]{@link module:ControlFlow.whilst}. To reflect the difference in
2072   * the order of operations, the arguments `test` and `iteratee` are switched.
2073   *
2074   * `doWhilst` is to `whilst` as `do while` is to `while` in plain JavaScript.
2075   *
2076   * @name doWhilst
2077   * @static
2078   * @memberOf module:ControlFlow
2079   * @method
2080   * @see [async.whilst]{@link module:ControlFlow.whilst}
2081   * @category Control Flow
2082   * @param {AsyncFunction} iteratee - A function which is called each time `test`
2083   * passes. Invoked with (callback).
2084   * @param {AsyncFunction} test - asynchronous truth test to perform after each
2085   * execution of `iteratee`. Invoked with (...args, callback), where `...args` are the
2086   * non-error args from the previous callback of `iteratee`.
2087   * @param {Function} [callback] - A callback which is called after the test
2088   * function has failed and repeated execution of `iteratee` has stopped.
2089   * `callback` will be passed an error and any arguments passed to the final
2090   * `iteratee`'s callback. Invoked with (err, [results]);
2091   * @returns {Promise} a promise, if no callback is passed
2092   */
2093  function doWhilst(iteratee, test, callback) {
2094      callback = onlyOnce(callback);
2095      var _fn = wrapAsync(iteratee);
2096      var _test = wrapAsync(test);
2097      var results;
2098  
2099      function next(err, ...args) {
2100          if (err) return callback(err);
2101          if (err === false) return;
2102          results = args;
2103          _test(...args, check);
2104      }
2105  
2106      function check(err, truth) {
2107          if (err) return callback(err);
2108          if (err === false) return;
2109          if (!truth) return callback(null, ...results);
2110          _fn(next);
2111      }
2112  
2113      return check(null, true);
2114  }
2115  
2116  var doWhilst$1 = awaitify(doWhilst, 3);
2117  
2118  /**
2119   * Like ['doWhilst']{@link module:ControlFlow.doWhilst}, except the `test` is inverted. Note the
2120   * argument ordering differs from `until`.
2121   *
2122   * @name doUntil
2123   * @static
2124   * @memberOf module:ControlFlow
2125   * @method
2126   * @see [async.doWhilst]{@link module:ControlFlow.doWhilst}
2127   * @category Control Flow
2128   * @param {AsyncFunction} iteratee - An async function which is called each time
2129   * `test` fails. Invoked with (callback).
2130   * @param {AsyncFunction} test - asynchronous truth test to perform after each
2131   * execution of `iteratee`. Invoked with (...args, callback), where `...args` are the
2132   * non-error args from the previous callback of `iteratee`
2133   * @param {Function} [callback] - A callback which is called after the test
2134   * function has passed and repeated execution of `iteratee` has stopped. `callback`
2135   * will be passed an error and any arguments passed to the final `iteratee`'s
2136   * callback. Invoked with (err, [results]);
2137   * @returns {Promise} a promise, if no callback is passed
2138   */
2139  function doUntil(iteratee, test, callback) {
2140      const _test = wrapAsync(test);
2141      return doWhilst$1(iteratee, (...args) => {
2142          const cb = args.pop();
2143          _test(...args, (err, truth) => cb (err, !truth));
2144      }, callback);
2145  }
2146  
2147  function _withoutIndex(iteratee) {
2148      return (value, index, callback) => iteratee(value, callback);
2149  }
2150  
2151  /**
2152   * Applies the function `iteratee` to each item in `coll`, in parallel.
2153   * The `iteratee` is called with an item from the list, and a callback for when
2154   * it has finished. If the `iteratee` passes an error to its `callback`, the
2155   * main `callback` (for the `each` function) is immediately called with the
2156   * error.
2157   *
2158   * Note, that since this function applies `iteratee` to each item in parallel,
2159   * there is no guarantee that the iteratee functions will complete in order.
2160   *
2161   * @name each
2162   * @static
2163   * @memberOf module:Collections
2164   * @method
2165   * @alias forEach
2166   * @category Collection
2167   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2168   * @param {AsyncFunction} iteratee - An async function to apply to
2169   * each item in `coll`. Invoked with (item, callback).
2170   * The array index is not passed to the iteratee.
2171   * If you need the index, use `eachOf`.
2172   * @param {Function} [callback] - A callback which is called when all
2173   * `iteratee` functions have finished, or an error occurs. Invoked with (err).
2174   * @returns {Promise} a promise, if a callback is omitted
2175   * @example
2176   *
2177   * // assuming openFiles is an array of file names and saveFile is a function
2178   * // to save the modified contents of that file:
2179   *
2180   * async.each(openFiles, saveFile, function(err){
2181   *   // if any of the saves produced an error, err would equal that error
2182   * });
2183   *
2184   * // assuming openFiles is an array of file names
2185   * async.each(openFiles, function(file, callback) {
2186   *
2187   *     // Perform operation on file here.
2188   *     console.log('Processing file ' + file);
2189   *
2190   *     if( file.length > 32 ) {
2191   *       console.log('This file name is too long');
2192   *       callback('File name too long');
2193   *     } else {
2194   *       // Do work to process file here
2195   *       console.log('File processed');
2196   *       callback();
2197   *     }
2198   * }, function(err) {
2199   *     // if any of the file processing produced an error, err would equal that error
2200   *     if( err ) {
2201   *       // One of the iterations produced an error.
2202   *       // All processing will now stop.
2203   *       console.log('A file failed to process');
2204   *     } else {
2205   *       console.log('All files have been processed successfully');
2206   *     }
2207   * });
2208   */
2209  function eachLimit(coll, iteratee, callback) {
2210      return eachOf$1(coll, _withoutIndex(wrapAsync(iteratee)), callback);
2211  }
2212  
2213  var each = awaitify(eachLimit, 3);
2214  
2215  /**
2216   * The same as [`each`]{@link module:Collections.each} but runs a maximum of `limit` async operations at a time.
2217   *
2218   * @name eachLimit
2219   * @static
2220   * @memberOf module:Collections
2221   * @method
2222   * @see [async.each]{@link module:Collections.each}
2223   * @alias forEachLimit
2224   * @category Collection
2225   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2226   * @param {number} limit - The maximum number of async operations at a time.
2227   * @param {AsyncFunction} iteratee - An async function to apply to each item in
2228   * `coll`.
2229   * The array index is not passed to the iteratee.
2230   * If you need the index, use `eachOfLimit`.
2231   * Invoked with (item, callback).
2232   * @param {Function} [callback] - A callback which is called when all
2233   * `iteratee` functions have finished, or an error occurs. Invoked with (err).
2234   * @returns {Promise} a promise, if a callback is omitted
2235   */
2236  function eachLimit$1(coll, limit, iteratee, callback) {
2237      return eachOfLimit(limit)(coll, _withoutIndex(wrapAsync(iteratee)), callback);
2238  }
2239  var eachLimit$2 = awaitify(eachLimit$1, 4);
2240  
2241  /**
2242   * The same as [`each`]{@link module:Collections.each} but runs only a single async operation at a time.
2243   *
2244   * Note, that unlike [`each`]{@link module:Collections.each}, this function applies iteratee to each item
2245   * in series and therefore the iteratee functions will complete in order.
2246  
2247   * @name eachSeries
2248   * @static
2249   * @memberOf module:Collections
2250   * @method
2251   * @see [async.each]{@link module:Collections.each}
2252   * @alias forEachSeries
2253   * @category Collection
2254   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2255   * @param {AsyncFunction} iteratee - An async function to apply to each
2256   * item in `coll`.
2257   * The array index is not passed to the iteratee.
2258   * If you need the index, use `eachOfSeries`.
2259   * Invoked with (item, callback).
2260   * @param {Function} [callback] - A callback which is called when all
2261   * `iteratee` functions have finished, or an error occurs. Invoked with (err).
2262   * @returns {Promise} a promise, if a callback is omitted
2263   */
2264  function eachSeries(coll, iteratee, callback) {
2265      return eachLimit$2(coll, 1, iteratee, callback)
2266  }
2267  var eachSeries$1 = awaitify(eachSeries, 3);
2268  
2269  /**
2270   * Wrap an async function and ensure it calls its callback on a later tick of
2271   * the event loop.  If the function already calls its callback on a next tick,
2272   * no extra deferral is added. This is useful for preventing stack overflows
2273   * (`RangeError: Maximum call stack size exceeded`) and generally keeping
2274   * [Zalgo](http://blog.izs.me/post/59142742143/designing-apis-for-asynchrony)
2275   * contained. ES2017 `async` functions are returned as-is -- they are immune
2276   * to Zalgo's corrupting influences, as they always resolve on a later tick.
2277   *
2278   * @name ensureAsync
2279   * @static
2280   * @memberOf module:Utils
2281   * @method
2282   * @category Util
2283   * @param {AsyncFunction} fn - an async function, one that expects a node-style
2284   * callback as its last argument.
2285   * @returns {AsyncFunction} Returns a wrapped function with the exact same call
2286   * signature as the function passed in.
2287   * @example
2288   *
2289   * function sometimesAsync(arg, callback) {
2290   *     if (cache[arg]) {
2291   *         return callback(null, cache[arg]); // this would be synchronous!!
2292   *     } else {
2293   *         doSomeIO(arg, callback); // this IO would be asynchronous
2294   *     }
2295   * }
2296   *
2297   * // this has a risk of stack overflows if many results are cached in a row
2298   * async.mapSeries(args, sometimesAsync, done);
2299   *
2300   * // this will defer sometimesAsync's callback if necessary,
2301   * // preventing stack overflows
2302   * async.mapSeries(args, async.ensureAsync(sometimesAsync), done);
2303   */
2304  function ensureAsync(fn) {
2305      if (isAsync(fn)) return fn;
2306      return function (...args/*, callback*/) {
2307          var callback = args.pop();
2308          var sync = true;
2309          args.push((...innerArgs) => {
2310              if (sync) {
2311                  setImmediate$1(() => callback(...innerArgs));
2312              } else {
2313                  callback(...innerArgs);
2314              }
2315          });
2316          fn.apply(this, args);
2317          sync = false;
2318      };
2319  }
2320  
2321  /**
2322   * Returns `true` if every element in `coll` satisfies an async test. If any
2323   * iteratee call returns `false`, the main `callback` is immediately called.
2324   *
2325   * @name every
2326   * @static
2327   * @memberOf module:Collections
2328   * @method
2329   * @alias all
2330   * @category Collection
2331   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2332   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
2333   * in the collection in parallel.
2334   * The iteratee must complete with a boolean result value.
2335   * Invoked with (item, callback).
2336   * @param {Function} [callback] - A callback which is called after all the
2337   * `iteratee` functions have finished. Result will be either `true` or `false`
2338   * depending on the values of the async tests. Invoked with (err, result).
2339   * @returns {Promise} a promise, if no callback provided
2340   * @example
2341   *
2342   * async.every(['file1','file2','file3'], function(filePath, callback) {
2343   *     fs.access(filePath, function(err) {
2344   *         callback(null, !err)
2345   *     });
2346   * }, function(err, result) {
2347   *     // if result is true then every file exists
2348   * });
2349   */
2350  function every(coll, iteratee, callback) {
2351      return _createTester(bool => !bool, res => !res)(eachOf$1, coll, iteratee, callback)
2352  }
2353  var every$1 = awaitify(every, 3);
2354  
2355  /**
2356   * The same as [`every`]{@link module:Collections.every} but runs a maximum of `limit` async operations at a time.
2357   *
2358   * @name everyLimit
2359   * @static
2360   * @memberOf module:Collections
2361   * @method
2362   * @see [async.every]{@link module:Collections.every}
2363   * @alias allLimit
2364   * @category Collection
2365   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2366   * @param {number} limit - The maximum number of async operations at a time.
2367   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
2368   * in the collection in parallel.
2369   * The iteratee must complete with a boolean result value.
2370   * Invoked with (item, callback).
2371   * @param {Function} [callback] - A callback which is called after all the
2372   * `iteratee` functions have finished. Result will be either `true` or `false`
2373   * depending on the values of the async tests. Invoked with (err, result).
2374   * @returns {Promise} a promise, if no callback provided
2375   */
2376  function everyLimit(coll, limit, iteratee, callback) {
2377      return _createTester(bool => !bool, res => !res)(eachOfLimit(limit), coll, iteratee, callback)
2378  }
2379  var everyLimit$1 = awaitify(everyLimit, 4);
2380  
2381  /**
2382   * The same as [`every`]{@link module:Collections.every} but runs only a single async operation at a time.
2383   *
2384   * @name everySeries
2385   * @static
2386   * @memberOf module:Collections
2387   * @method
2388   * @see [async.every]{@link module:Collections.every}
2389   * @alias allSeries
2390   * @category Collection
2391   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2392   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
2393   * in the collection in series.
2394   * The iteratee must complete with a boolean result value.
2395   * Invoked with (item, callback).
2396   * @param {Function} [callback] - A callback which is called after all the
2397   * `iteratee` functions have finished. Result will be either `true` or `false`
2398   * depending on the values of the async tests. Invoked with (err, result).
2399   * @returns {Promise} a promise, if no callback provided
2400   */
2401  function everySeries(coll, iteratee, callback) {
2402      return _createTester(bool => !bool, res => !res)(eachOfSeries$1, coll, iteratee, callback)
2403  }
2404  var everySeries$1 = awaitify(everySeries, 3);
2405  
2406  function filterArray(eachfn, arr, iteratee, callback) {
2407      var truthValues = new Array(arr.length);
2408      eachfn(arr, (x, index, iterCb) => {
2409          iteratee(x, (err, v) => {
2410              truthValues[index] = !!v;
2411              iterCb(err);
2412          });
2413      }, err => {
2414          if (err) return callback(err);
2415          var results = [];
2416          for (var i = 0; i < arr.length; i++) {
2417              if (truthValues[i]) results.push(arr[i]);
2418          }
2419          callback(null, results);
2420      });
2421  }
2422  
2423  function filterGeneric(eachfn, coll, iteratee, callback) {
2424      var results = [];
2425      eachfn(coll, (x, index, iterCb) => {
2426          iteratee(x, (err, v) => {
2427              if (err) return iterCb(err);
2428              if (v) {
2429                  results.push({index, value: x});
2430              }
2431              iterCb(err);
2432          });
2433      }, err => {
2434          if (err) return callback(err);
2435          callback(null, results
2436              .sort((a, b) => a.index - b.index)
2437              .map(v => v.value));
2438      });
2439  }
2440  
2441  function _filter(eachfn, coll, iteratee, callback) {
2442      var filter = isArrayLike(coll) ? filterArray : filterGeneric;
2443      return filter(eachfn, coll, wrapAsync(iteratee), callback);
2444  }
2445  
2446  /**
2447   * Returns a new array of all the values in `coll` which pass an async truth
2448   * test. This operation is performed in parallel, but the results array will be
2449   * in the same order as the original.
2450   *
2451   * @name filter
2452   * @static
2453   * @memberOf module:Collections
2454   * @method
2455   * @alias select
2456   * @category Collection
2457   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2458   * @param {Function} iteratee - A truth test to apply to each item in `coll`.
2459   * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
2460   * with a boolean argument once it has completed. Invoked with (item, callback).
2461   * @param {Function} [callback] - A callback which is called after all the
2462   * `iteratee` functions have finished. Invoked with (err, results).
2463   * @returns {Promise} a promise, if no callback provided
2464   * @example
2465   *
2466   * async.filter(['file1','file2','file3'], function(filePath, callback) {
2467   *     fs.access(filePath, function(err) {
2468   *         callback(null, !err)
2469   *     });
2470   * }, function(err, results) {
2471   *     // results now equals an array of the existing files
2472   * });
2473   */
2474  function filter (coll, iteratee, callback) {
2475      return _filter(eachOf$1, coll, iteratee, callback)
2476  }
2477  var filter$1 = awaitify(filter, 3);
2478  
2479  /**
2480   * The same as [`filter`]{@link module:Collections.filter} but runs a maximum of `limit` async operations at a
2481   * time.
2482   *
2483   * @name filterLimit
2484   * @static
2485   * @memberOf module:Collections
2486   * @method
2487   * @see [async.filter]{@link module:Collections.filter}
2488   * @alias selectLimit
2489   * @category Collection
2490   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2491   * @param {number} limit - The maximum number of async operations at a time.
2492   * @param {Function} iteratee - A truth test to apply to each item in `coll`.
2493   * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
2494   * with a boolean argument once it has completed. Invoked with (item, callback).
2495   * @param {Function} [callback] - A callback which is called after all the
2496   * `iteratee` functions have finished. Invoked with (err, results).
2497   * @returns {Promise} a promise, if no callback provided
2498   */
2499  function filterLimit (coll, limit, iteratee, callback) {
2500      return _filter(eachOfLimit(limit), coll, iteratee, callback)
2501  }
2502  var filterLimit$1 = awaitify(filterLimit, 4);
2503  
2504  /**
2505   * The same as [`filter`]{@link module:Collections.filter} but runs only a single async operation at a time.
2506   *
2507   * @name filterSeries
2508   * @static
2509   * @memberOf module:Collections
2510   * @method
2511   * @see [async.filter]{@link module:Collections.filter}
2512   * @alias selectSeries
2513   * @category Collection
2514   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2515   * @param {Function} iteratee - A truth test to apply to each item in `coll`.
2516   * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
2517   * with a boolean argument once it has completed. Invoked with (item, callback).
2518   * @param {Function} [callback] - A callback which is called after all the
2519   * `iteratee` functions have finished. Invoked with (err, results)
2520   * @returns {Promise} a promise, if no callback provided
2521   */
2522  function filterSeries (coll, iteratee, callback) {
2523      return _filter(eachOfSeries$1, coll, iteratee, callback)
2524  }
2525  var filterSeries$1 = awaitify(filterSeries, 3);
2526  
2527  /**
2528   * Calls the asynchronous function `fn` with a callback parameter that allows it
2529   * to call itself again, in series, indefinitely.
2530  
2531   * If an error is passed to the callback then `errback` is called with the
2532   * error, and execution stops, otherwise it will never be called.
2533   *
2534   * @name forever
2535   * @static
2536   * @memberOf module:ControlFlow
2537   * @method
2538   * @category Control Flow
2539   * @param {AsyncFunction} fn - an async function to call repeatedly.
2540   * Invoked with (next).
2541   * @param {Function} [errback] - when `fn` passes an error to it's callback,
2542   * this function will be called, and execution stops. Invoked with (err).
2543   * @returns {Promise} a promise that rejects if an error occurs and an errback
2544   * is not passed
2545   * @example
2546   *
2547   * async.forever(
2548   *     function(next) {
2549   *         // next is suitable for passing to things that need a callback(err [, whatever]);
2550   *         // it will result in this function being called again.
2551   *     },
2552   *     function(err) {
2553   *         // if next is called with a value in its first parameter, it will appear
2554   *         // in here as 'err', and execution will stop.
2555   *     }
2556   * );
2557   */
2558  function forever(fn, errback) {
2559      var done = onlyOnce(errback);
2560      var task = wrapAsync(ensureAsync(fn));
2561  
2562      function next(err) {
2563          if (err) return done(err);
2564          if (err === false) return;
2565          task(next);
2566      }
2567      return next();
2568  }
2569  var forever$1 = awaitify(forever, 2);
2570  
2571  /**
2572   * The same as [`groupBy`]{@link module:Collections.groupBy} but runs a maximum of `limit` async operations at a time.
2573   *
2574   * @name groupByLimit
2575   * @static
2576   * @memberOf module:Collections
2577   * @method
2578   * @see [async.groupBy]{@link module:Collections.groupBy}
2579   * @category Collection
2580   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2581   * @param {number} limit - The maximum number of async operations at a time.
2582   * @param {AsyncFunction} iteratee - An async function to apply to each item in
2583   * `coll`.
2584   * The iteratee should complete with a `key` to group the value under.
2585   * Invoked with (value, callback).
2586   * @param {Function} [callback] - A callback which is called when all `iteratee`
2587   * functions have finished, or an error occurs. Result is an `Object` whoses
2588   * properties are arrays of values which returned the corresponding key.
2589   * @returns {Promise} a promise, if no callback is passed
2590   */
2591  function groupByLimit(coll, limit, iteratee, callback) {
2592      var _iteratee = wrapAsync(iteratee);
2593      return mapLimit$1(coll, limit, (val, iterCb) => {
2594          _iteratee(val, (err, key) => {
2595              if (err) return iterCb(err);
2596              return iterCb(err, {key, val});
2597          });
2598      }, (err, mapResults) => {
2599          var result = {};
2600          // from MDN, handle object having an `hasOwnProperty` prop
2601          var {hasOwnProperty} = Object.prototype;
2602  
2603          for (var i = 0; i < mapResults.length; i++) {
2604              if (mapResults[i]) {
2605                  var {key} = mapResults[i];
2606                  var {val} = mapResults[i];
2607  
2608                  if (hasOwnProperty.call(result, key)) {
2609                      result[key].push(val);
2610                  } else {
2611                      result[key] = [val];
2612                  }
2613              }
2614          }
2615  
2616          return callback(err, result);
2617      });
2618  }
2619  
2620  var groupByLimit$1 = awaitify(groupByLimit, 4);
2621  
2622  /**
2623   * Returns a new object, where each value corresponds to an array of items, from
2624   * `coll`, that returned the corresponding key. That is, the keys of the object
2625   * correspond to the values passed to the `iteratee` callback.
2626   *
2627   * Note: Since this function applies the `iteratee` to each item in parallel,
2628   * there is no guarantee that the `iteratee` functions will complete in order.
2629   * However, the values for each key in the `result` will be in the same order as
2630   * the original `coll`. For Objects, the values will roughly be in the order of
2631   * the original Objects' keys (but this can vary across JavaScript engines).
2632   *
2633   * @name groupBy
2634   * @static
2635   * @memberOf module:Collections
2636   * @method
2637   * @category Collection
2638   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2639   * @param {AsyncFunction} iteratee - An async function to apply to each item in
2640   * `coll`.
2641   * The iteratee should complete with a `key` to group the value under.
2642   * Invoked with (value, callback).
2643   * @param {Function} [callback] - A callback which is called when all `iteratee`
2644   * functions have finished, or an error occurs. Result is an `Object` whoses
2645   * properties are arrays of values which returned the corresponding key.
2646   * @returns {Promise} a promise, if no callback is passed
2647   * @example
2648   *
2649   * async.groupBy(['userId1', 'userId2', 'userId3'], function(userId, callback) {
2650   *     db.findById(userId, function(err, user) {
2651   *         if (err) return callback(err);
2652   *         return callback(null, user.age);
2653   *     });
2654   * }, function(err, result) {
2655   *     // result is object containing the userIds grouped by age
2656   *     // e.g. { 30: ['userId1', 'userId3'], 42: ['userId2']};
2657   * });
2658   */
2659  function groupBy (coll, iteratee, callback) {
2660      return groupByLimit$1(coll, Infinity, iteratee, callback)
2661  }
2662  
2663  /**
2664   * The same as [`groupBy`]{@link module:Collections.groupBy} but runs only a single async operation at a time.
2665   *
2666   * @name groupBySeries
2667   * @static
2668   * @memberOf module:Collections
2669   * @method
2670   * @see [async.groupBy]{@link module:Collections.groupBy}
2671   * @category Collection
2672   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
2673   * @param {AsyncFunction} iteratee - An async function to apply to each item in
2674   * `coll`.
2675   * The iteratee should complete with a `key` to group the value under.
2676   * Invoked with (value, callback).
2677   * @param {Function} [callback] - A callback which is called when all `iteratee`
2678   * functions have finished, or an error occurs. Result is an `Object` whoses
2679   * properties are arrays of values which returned the corresponding key.
2680   * @returns {Promise} a promise, if no callback is passed
2681   */
2682  function groupBySeries (coll, iteratee, callback) {
2683      return groupByLimit$1(coll, 1, iteratee, callback)
2684  }
2685  
2686  /**
2687   * Logs the result of an `async` function to the `console`. Only works in
2688   * Node.js or in browsers that support `console.log` and `console.error` (such
2689   * as FF and Chrome). If multiple arguments are returned from the async
2690   * function, `console.log` is called on each argument in order.
2691   *
2692   * @name log
2693   * @static
2694   * @memberOf module:Utils
2695   * @method
2696   * @category Util
2697   * @param {AsyncFunction} function - The function you want to eventually apply
2698   * all arguments to.
2699   * @param {...*} arguments... - Any number of arguments to apply to the function.
2700   * @example
2701   *
2702   * // in a module
2703   * var hello = function(name, callback) {
2704   *     setTimeout(function() {
2705   *         callback(null, 'hello ' + name);
2706   *     }, 1000);
2707   * };
2708   *
2709   * // in the node repl
2710   * node> async.log(hello, 'world');
2711   * 'hello world'
2712   */
2713  var log = consoleFunc('log');
2714  
2715  /**
2716   * The same as [`mapValues`]{@link module:Collections.mapValues} but runs a maximum of `limit` async operations at a
2717   * time.
2718   *
2719   * @name mapValuesLimit
2720   * @static
2721   * @memberOf module:Collections
2722   * @method
2723   * @see [async.mapValues]{@link module:Collections.mapValues}
2724   * @category Collection
2725   * @param {Object} obj - A collection to iterate over.
2726   * @param {number} limit - The maximum number of async operations at a time.
2727   * @param {AsyncFunction} iteratee - A function to apply to each value and key
2728   * in `coll`.
2729   * The iteratee should complete with the transformed value as its result.
2730   * Invoked with (value, key, callback).
2731   * @param {Function} [callback] - A callback which is called when all `iteratee`
2732   * functions have finished, or an error occurs. `result` is a new object consisting
2733   * of each key from `obj`, with each transformed value on the right-hand side.
2734   * Invoked with (err, result).
2735   * @returns {Promise} a promise, if no callback is passed
2736   */
2737  function mapValuesLimit(obj, limit, iteratee, callback) {
2738      callback = once(callback);
2739      var newObj = {};
2740      var _iteratee = wrapAsync(iteratee);
2741      return eachOfLimit(limit)(obj, (val, key, next) => {
2742          _iteratee(val, key, (err, result) => {
2743              if (err) return next(err);
2744              newObj[key] = result;
2745              next(err);
2746          });
2747      }, err => callback(err, newObj));
2748  }
2749  
2750  var mapValuesLimit$1 = awaitify(mapValuesLimit, 4);
2751  
2752  /**
2753   * A relative of [`map`]{@link module:Collections.map}, designed for use with objects.
2754   *
2755   * Produces a new Object by mapping each value of `obj` through the `iteratee`
2756   * function. The `iteratee` is called each `value` and `key` from `obj` and a
2757   * callback for when it has finished processing. Each of these callbacks takes
2758   * two arguments: an `error`, and the transformed item from `obj`. If `iteratee`
2759   * passes an error to its callback, the main `callback` (for the `mapValues`
2760   * function) is immediately called with the error.
2761   *
2762   * Note, the order of the keys in the result is not guaranteed.  The keys will
2763   * be roughly in the order they complete, (but this is very engine-specific)
2764   *
2765   * @name mapValues
2766   * @static
2767   * @memberOf module:Collections
2768   * @method
2769   * @category Collection
2770   * @param {Object} obj - A collection to iterate over.
2771   * @param {AsyncFunction} iteratee - A function to apply to each value and key
2772   * in `coll`.
2773   * The iteratee should complete with the transformed value as its result.
2774   * Invoked with (value, key, callback).
2775   * @param {Function} [callback] - A callback which is called when all `iteratee`
2776   * functions have finished, or an error occurs. `result` is a new object consisting
2777   * of each key from `obj`, with each transformed value on the right-hand side.
2778   * Invoked with (err, result).
2779   * @returns {Promise} a promise, if no callback is passed
2780   * @example
2781   *
2782   * async.mapValues({
2783   *     f1: 'file1',
2784   *     f2: 'file2',
2785   *     f3: 'file3'
2786   * }, function (file, key, callback) {
2787   *   fs.stat(file, callback);
2788   * }, function(err, result) {
2789   *     // result is now a map of stats for each file, e.g.
2790   *     // {
2791   *     //     f1: [stats for file1],
2792   *     //     f2: [stats for file2],
2793   *     //     f3: [stats for file3]
2794   *     // }
2795   * });
2796   */
2797  function mapValues(obj, iteratee, callback) {
2798      return mapValuesLimit$1(obj, Infinity, iteratee, callback)
2799  }
2800  
2801  /**
2802   * The same as [`mapValues`]{@link module:Collections.mapValues} but runs only a single async operation at a time.
2803   *
2804   * @name mapValuesSeries
2805   * @static
2806   * @memberOf module:Collections
2807   * @method
2808   * @see [async.mapValues]{@link module:Collections.mapValues}
2809   * @category Collection
2810   * @param {Object} obj - A collection to iterate over.
2811   * @param {AsyncFunction} iteratee - A function to apply to each value and key
2812   * in `coll`.
2813   * The iteratee should complete with the transformed value as its result.
2814   * Invoked with (value, key, callback).
2815   * @param {Function} [callback] - A callback which is called when all `iteratee`
2816   * functions have finished, or an error occurs. `result` is a new object consisting
2817   * of each key from `obj`, with each transformed value on the right-hand side.
2818   * Invoked with (err, result).
2819   * @returns {Promise} a promise, if no callback is passed
2820   */
2821  function mapValuesSeries(obj, iteratee, callback) {
2822      return mapValuesLimit$1(obj, 1, iteratee, callback)
2823  }
2824  
2825  /**
2826   * Caches the results of an async function. When creating a hash to store
2827   * function results against, the callback is omitted from the hash and an
2828   * optional hash function can be used.
2829   *
2830   * **Note: if the async function errs, the result will not be cached and
2831   * subsequent calls will call the wrapped function.**
2832   *
2833   * If no hash function is specified, the first argument is used as a hash key,
2834   * which may work reasonably if it is a string or a data type that converts to a
2835   * distinct string. Note that objects and arrays will not behave reasonably.
2836   * Neither will cases where the other arguments are significant. In such cases,
2837   * specify your own hash function.
2838   *
2839   * The cache of results is exposed as the `memo` property of the function
2840   * returned by `memoize`.
2841   *
2842   * @name memoize
2843   * @static
2844   * @memberOf module:Utils
2845   * @method
2846   * @category Util
2847   * @param {AsyncFunction} fn - The async function to proxy and cache results from.
2848   * @param {Function} hasher - An optional function for generating a custom hash
2849   * for storing results. It has all the arguments applied to it apart from the
2850   * callback, and must be synchronous.
2851   * @returns {AsyncFunction} a memoized version of `fn`
2852   * @example
2853   *
2854   * var slow_fn = function(name, callback) {
2855   *     // do something
2856   *     callback(null, result);
2857   * };
2858   * var fn = async.memoize(slow_fn);
2859   *
2860   * // fn can now be used as if it were slow_fn
2861   * fn('some name', function() {
2862   *     // callback
2863   * });
2864   */
2865  function memoize(fn, hasher = v => v) {
2866      var memo = Object.create(null);
2867      var queues = Object.create(null);
2868      var _fn = wrapAsync(fn);
2869      var memoized = initialParams((args, callback) => {
2870          var key = hasher(...args);
2871          if (key in memo) {
2872              setImmediate$1(() => callback(null, ...memo[key]));
2873          } else if (key in queues) {
2874              queues[key].push(callback);
2875          } else {
2876              queues[key] = [callback];
2877              _fn(...args, (err, ...resultArgs) => {
2878                  // #1465 don't memoize if an error occurred
2879                  if (!err) {
2880                      memo[key] = resultArgs;
2881                  }
2882                  var q = queues[key];
2883                  delete queues[key];
2884                  for (var i = 0, l = q.length; i < l; i++) {
2885                      q[i](err, ...resultArgs);
2886                  }
2887              });
2888          }
2889      });
2890      memoized.memo = memo;
2891      memoized.unmemoized = fn;
2892      return memoized;
2893  }
2894  
2895  /**
2896   * Calls `callback` on a later loop around the event loop. In Node.js this just
2897   * calls `process.nextTick`.  In the browser it will use `setImmediate` if
2898   * available, otherwise `setTimeout(callback, 0)`, which means other higher
2899   * priority events may precede the execution of `callback`.
2900   *
2901   * This is used internally for browser-compatibility purposes.
2902   *
2903   * @name nextTick
2904   * @static
2905   * @memberOf module:Utils
2906   * @method
2907   * @see [async.setImmediate]{@link module:Utils.setImmediate}
2908   * @category Util
2909   * @param {Function} callback - The function to call on a later loop around
2910   * the event loop. Invoked with (args...).
2911   * @param {...*} args... - any number of additional arguments to pass to the
2912   * callback on the next tick.
2913   * @example
2914   *
2915   * var call_order = [];
2916   * async.nextTick(function() {
2917   *     call_order.push('two');
2918   *     // call_order now equals ['one','two']
2919   * });
2920   * call_order.push('one');
2921   *
2922   * async.setImmediate(function (a, b, c) {
2923   *     // a, b, and c equal 1, 2, and 3
2924   * }, 1, 2, 3);
2925   */
2926  var _defer$1;
2927  
2928  if (hasNextTick) {
2929      _defer$1 = process.nextTick;
2930  } else if (hasSetImmediate) {
2931      _defer$1 = setImmediate;
2932  } else {
2933      _defer$1 = fallback;
2934  }
2935  
2936  var nextTick = wrap(_defer$1);
2937  
2938  var _parallel = awaitify((eachfn, tasks, callback) => {
2939      var results = isArrayLike(tasks) ? [] : {};
2940  
2941      eachfn(tasks, (task, key, taskCb) => {
2942          wrapAsync(task)((err, ...result) => {
2943              if (result.length < 2) {
2944                  [result] = result;
2945              }
2946              results[key] = result;
2947              taskCb(err);
2948          });
2949      }, err => callback(err, results));
2950  }, 3);
2951  
2952  /**
2953   * Run the `tasks` collection of functions in parallel, without waiting until
2954   * the previous function has completed. If any of the functions pass an error to
2955   * its callback, the main `callback` is immediately called with the value of the
2956   * error. Once the `tasks` have completed, the results are passed to the final
2957   * `callback` as an array.
2958   *
2959   * **Note:** `parallel` is about kicking-off I/O tasks in parallel, not about
2960   * parallel execution of code.  If your tasks do not use any timers or perform
2961   * any I/O, they will actually be executed in series.  Any synchronous setup
2962   * sections for each task will happen one after the other.  JavaScript remains
2963   * single-threaded.
2964   *
2965   * **Hint:** Use [`reflect`]{@link module:Utils.reflect} to continue the
2966   * execution of other tasks when a task fails.
2967   *
2968   * It is also possible to use an object instead of an array. Each property will
2969   * be run as a function and the results will be passed to the final `callback`
2970   * as an object instead of an array. This can be a more readable way of handling
2971   * results from {@link async.parallel}.
2972   *
2973   * @name parallel
2974   * @static
2975   * @memberOf module:ControlFlow
2976   * @method
2977   * @category Control Flow
2978   * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection of
2979   * [async functions]{@link AsyncFunction} to run.
2980   * Each async function can complete with any number of optional `result` values.
2981   * @param {Function} [callback] - An optional callback to run once all the
2982   * functions have completed successfully. This function gets a results array
2983   * (or object) containing all the result arguments passed to the task callbacks.
2984   * Invoked with (err, results).
2985   * @returns {Promise} a promise, if a callback is not passed
2986   *
2987   * @example
2988   * async.parallel([
2989   *     function(callback) {
2990   *         setTimeout(function() {
2991   *             callback(null, 'one');
2992   *         }, 200);
2993   *     },
2994   *     function(callback) {
2995   *         setTimeout(function() {
2996   *             callback(null, 'two');
2997   *         }, 100);
2998   *     }
2999   * ],
3000   * // optional callback
3001   * function(err, results) {
3002   *     // the results array will equal ['one','two'] even though
3003   *     // the second function had a shorter timeout.
3004   * });
3005   *
3006   * // an example using an object instead of an array
3007   * async.parallel({
3008   *     one: function(callback) {
3009   *         setTimeout(function() {
3010   *             callback(null, 1);
3011   *         }, 200);
3012   *     },
3013   *     two: function(callback) {
3014   *         setTimeout(function() {
3015   *             callback(null, 2);
3016   *         }, 100);
3017   *     }
3018   * }, function(err, results) {
3019   *     // results is now equals to: {one: 1, two: 2}
3020   * });
3021   */
3022  function parallel(tasks, callback) {
3023      return _parallel(eachOf$1, tasks, callback);
3024  }
3025  
3026  /**
3027   * The same as [`parallel`]{@link module:ControlFlow.parallel} but runs a maximum of `limit` async operations at a
3028   * time.
3029   *
3030   * @name parallelLimit
3031   * @static
3032   * @memberOf module:ControlFlow
3033   * @method
3034   * @see [async.parallel]{@link module:ControlFlow.parallel}
3035   * @category Control Flow
3036   * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection of
3037   * [async functions]{@link AsyncFunction} to run.
3038   * Each async function can complete with any number of optional `result` values.
3039   * @param {number} limit - The maximum number of async operations at a time.
3040   * @param {Function} [callback] - An optional callback to run once all the
3041   * functions have completed successfully. This function gets a results array
3042   * (or object) containing all the result arguments passed to the task callbacks.
3043   * Invoked with (err, results).
3044   * @returns {Promise} a promise, if a callback is not passed
3045   */
3046  function parallelLimit(tasks, limit, callback) {
3047      return _parallel(eachOfLimit(limit), tasks, callback);
3048  }
3049  
3050  /**
3051   * A queue of tasks for the worker function to complete.
3052   * @typedef {Iterable} QueueObject
3053   * @memberOf module:ControlFlow
3054   * @property {Function} length - a function returning the number of items
3055   * waiting to be processed. Invoke with `queue.length()`.
3056   * @property {boolean} started - a boolean indicating whether or not any
3057   * items have been pushed and processed by the queue.
3058   * @property {Function} running - a function returning the number of items
3059   * currently being processed. Invoke with `queue.running()`.
3060   * @property {Function} workersList - a function returning the array of items
3061   * currently being processed. Invoke with `queue.workersList()`.
3062   * @property {Function} idle - a function returning false if there are items
3063   * waiting or being processed, or true if not. Invoke with `queue.idle()`.
3064   * @property {number} concurrency - an integer for determining how many `worker`
3065   * functions should be run in parallel. This property can be changed after a
3066   * `queue` is created to alter the concurrency on-the-fly.
3067   * @property {number} payload - an integer that specifies how many items are
3068   * passed to the worker function at a time. only applies if this is a
3069   * [cargo]{@link module:ControlFlow.cargo} object
3070   * @property {AsyncFunction} push - add a new task to the `queue`. Calls `callback`
3071   * once the `worker` has finished processing the task. Instead of a single task,
3072   * a `tasks` array can be submitted. The respective callback is used for every
3073   * task in the list. Invoke with `queue.push(task, [callback])`,
3074   * @property {AsyncFunction} unshift - add a new task to the front of the `queue`.
3075   * Invoke with `queue.unshift(task, [callback])`.
3076   * @property {AsyncFunction} pushAsync - the same as `q.push`, except this returns
3077   * a promise that rejects if an error occurs.
3078   * @property {AsyncFunction} unshirtAsync - the same as `q.unshift`, except this returns
3079   * a promise that rejects if an error occurs.
3080   * @property {Function} remove - remove items from the queue that match a test
3081   * function.  The test function will be passed an object with a `data` property,
3082   * and a `priority` property, if this is a
3083   * [priorityQueue]{@link module:ControlFlow.priorityQueue} object.
3084   * Invoked with `queue.remove(testFn)`, where `testFn` is of the form
3085   * `function ({data, priority}) {}` and returns a Boolean.
3086   * @property {Function} saturated - a function that sets a callback that is
3087   * called when the number of running workers hits the `concurrency` limit, and
3088   * further tasks will be queued.  If the callback is omitted, `q.saturated()`
3089   * returns a promise for the next occurrence.
3090   * @property {Function} unsaturated - a function that sets a callback that is
3091   * called when the number of running workers is less than the `concurrency` &
3092   * `buffer` limits, and further tasks will not be queued. If the callback is
3093   * omitted, `q.unsaturated()` returns a promise for the next occurrence.
3094   * @property {number} buffer - A minimum threshold buffer in order to say that
3095   * the `queue` is `unsaturated`.
3096   * @property {Function} empty - a function that sets a callback that is called
3097   * when the last item from the `queue` is given to a `worker`. If the callback
3098   * is omitted, `q.empty()` returns a promise for the next occurrence.
3099   * @property {Function} drain - a function that sets a callback that is called
3100   * when the last item from the `queue` has returned from the `worker`. If the
3101   * callback is omitted, `q.drain()` returns a promise for the next occurrence.
3102   * @property {Function} error - a function that sets a callback that is called
3103   * when a task errors. Has the signature `function(error, task)`. If the
3104   * callback is omitted, `error()` returns a promise that rejects on the next
3105   * error.
3106   * @property {boolean} paused - a boolean for determining whether the queue is
3107   * in a paused state.
3108   * @property {Function} pause - a function that pauses the processing of tasks
3109   * until `resume()` is called. Invoke with `queue.pause()`.
3110   * @property {Function} resume - a function that resumes the processing of
3111   * queued tasks when the queue is paused. Invoke with `queue.resume()`.
3112   * @property {Function} kill - a function that removes the `drain` callback and
3113   * empties remaining tasks from the queue forcing it to go idle. No more tasks
3114   * should be pushed to the queue after calling this function. Invoke with `queue.kill()`.
3115   *
3116   * @example
3117   * const q = aync.queue(worker, 2)
3118   * q.push(item1)
3119   * q.push(item2)
3120   * q.push(item3)
3121   * // queues are iterable, spread into an array to inspect
3122   * const items = [...q] // [item1, item2, item3]
3123   * // or use for of
3124   * for (let item of q) {
3125   *     console.log(item)
3126   * }
3127   *
3128   * q.drain(() => {
3129   *     console.log('all done')
3130   * })
3131   * // or
3132   * await q.drain()
3133   */
3134  
3135  /**
3136   * Creates a `queue` object with the specified `concurrency`. Tasks added to the
3137   * `queue` are processed in parallel (up to the `concurrency` limit). If all
3138   * `worker`s are in progress, the task is queued until one becomes available.
3139   * Once a `worker` completes a `task`, that `task`'s callback is called.
3140   *
3141   * @name queue
3142   * @static
3143   * @memberOf module:ControlFlow
3144   * @method
3145   * @category Control Flow
3146   * @param {AsyncFunction} worker - An async function for processing a queued task.
3147   * If you want to handle errors from an individual task, pass a callback to
3148   * `q.push()`. Invoked with (task, callback).
3149   * @param {number} [concurrency=1] - An `integer` for determining how many
3150   * `worker` functions should be run in parallel.  If omitted, the concurrency
3151   * defaults to `1`.  If the concurrency is `0`, an error is thrown.
3152   * @returns {module:ControlFlow.QueueObject} A queue object to manage the tasks. Callbacks can be
3153   * attached as certain properties to listen for specific events during the
3154   * lifecycle of the queue.
3155   * @example
3156   *
3157   * // create a queue object with concurrency 2
3158   * var q = async.queue(function(task, callback) {
3159   *     console.log('hello ' + task.name);
3160   *     callback();
3161   * }, 2);
3162   *
3163   * // assign a callback
3164   * q.drain(function() {
3165   *     console.log('all items have been processed');
3166   * });
3167   * // or await the end
3168   * await q.drain()
3169   *
3170   * // assign an error callback
3171   * q.error(function(err, task) {
3172   *     console.error('task experienced an error');
3173   * });
3174   *
3175   * // add some items to the queue
3176   * q.push({name: 'foo'}, function(err) {
3177   *     console.log('finished processing foo');
3178   * });
3179   * // callback is optional
3180   * q.push({name: 'bar'});
3181   *
3182   * // add some items to the queue (batch-wise)
3183   * q.push([{name: 'baz'},{name: 'bay'},{name: 'bax'}], function(err) {
3184   *     console.log('finished processing item');
3185   * });
3186   *
3187   * // add some items to the front of the queue
3188   * q.unshift({name: 'bar'}, function (err) {
3189   *     console.log('finished processing bar');
3190   * });
3191   */
3192  function queue$1 (worker, concurrency) {
3193      var _worker = wrapAsync(worker);
3194      return queue((items, cb) => {
3195          _worker(items[0], cb);
3196      }, concurrency, 1);
3197  }
3198  
3199  // Binary min-heap implementation used for priority queue.
3200  // Implementation is stable, i.e. push time is considered for equal priorities
3201  class Heap {
3202      constructor() {
3203          this.heap = [];
3204          this.pushCount = Number.MIN_SAFE_INTEGER;
3205      }
3206  
3207      get length() {
3208          return this.heap.length;
3209      }
3210  
3211      empty () {
3212          this.heap = [];
3213          return this;
3214      }
3215  
3216      percUp(index) {
3217          let p;
3218  
3219          while (index > 0 && smaller(this.heap[index], this.heap[p=parent(index)])) {
3220              let t = this.heap[index];
3221              this.heap[index] = this.heap[p];
3222              this.heap[p] = t;
3223  
3224              index = p;
3225          }
3226      }
3227  
3228      percDown(index) {
3229          let l;
3230  
3231          while ((l=leftChi(index)) < this.heap.length) {
3232              if (l+1 < this.heap.length && smaller(this.heap[l+1], this.heap[l])) {
3233                  l = l+1;
3234              }
3235  
3236              if (smaller(this.heap[index], this.heap[l])) {
3237                  break;
3238              }
3239  
3240              let t = this.heap[index];
3241              this.heap[index] = this.heap[l];
3242              this.heap[l] = t;
3243  
3244              index = l;
3245          }
3246      }
3247  
3248      push(node) {
3249          node.pushCount = ++this.pushCount;
3250          this.heap.push(node);
3251          this.percUp(this.heap.length-1);
3252      }
3253  
3254      unshift(node) {
3255          return this.heap.push(node);
3256      }
3257  
3258      shift() {
3259          let [top] = this.heap;
3260  
3261          this.heap[0] = this.heap[this.heap.length-1];
3262          this.heap.pop();
3263          this.percDown(0);
3264  
3265          return top;
3266      }
3267  
3268      toArray() {
3269          return [...this];
3270      }
3271  
3272      *[Symbol.iterator] () {
3273          for (let i = 0; i < this.heap.length; i++) {
3274              yield this.heap[i].data;
3275          }
3276      }
3277  
3278      remove (testFn) {
3279          let j = 0;
3280          for (let i = 0; i < this.heap.length; i++) {
3281              if (!testFn(this.heap[i])) {
3282                  this.heap[j] = this.heap[i];
3283                  j++;
3284              }
3285          }
3286  
3287          this.heap.splice(j);
3288  
3289          for (let i = parent(this.heap.length-1); i >= 0; i--) {
3290              this.percDown(i);
3291          }
3292  
3293          return this;
3294      }
3295  }
3296  
3297  function leftChi(i) {
3298      return (i<<1)+1;
3299  }
3300  
3301  function parent(i) {
3302      return ((i+1)>>1)-1;
3303  }
3304  
3305  function smaller(x, y) {
3306      if (x.priority !== y.priority) {
3307          return x.priority < y.priority;
3308      }
3309      else {
3310          return x.pushCount < y.pushCount;
3311      }
3312  }
3313  
3314  /**
3315   * The same as [async.queue]{@link module:ControlFlow.queue} only tasks are assigned a priority and
3316   * completed in ascending priority order.
3317   *
3318   * @name priorityQueue
3319   * @static
3320   * @memberOf module:ControlFlow
3321   * @method
3322   * @see [async.queue]{@link module:ControlFlow.queue}
3323   * @category Control Flow
3324   * @param {AsyncFunction} worker - An async function for processing a queued task.
3325   * If you want to handle errors from an individual task, pass a callback to
3326   * `q.push()`.
3327   * Invoked with (task, callback).
3328   * @param {number} concurrency - An `integer` for determining how many `worker`
3329   * functions should be run in parallel.  If omitted, the concurrency defaults to
3330   * `1`.  If the concurrency is `0`, an error is thrown.
3331   * @returns {module:ControlFlow.QueueObject} A priorityQueue object to manage the tasks. There are two
3332   * differences between `queue` and `priorityQueue` objects:
3333   * * `push(task, priority, [callback])` - `priority` should be a number. If an
3334   *   array of `tasks` is given, all tasks will be assigned the same priority.
3335   * * The `unshift` method was removed.
3336   */
3337  function priorityQueue(worker, concurrency) {
3338      // Start with a normal queue
3339      var q = queue$1(worker, concurrency);
3340  
3341      q._tasks = new Heap();
3342  
3343      // Override push to accept second parameter representing priority
3344      q.push = function(data, priority = 0, callback = () => {}) {
3345          if (typeof callback !== 'function') {
3346              throw new Error('task callback must be a function');
3347          }
3348          q.started = true;
3349          if (!Array.isArray(data)) {
3350              data = [data];
3351          }
3352          if (data.length === 0 && q.idle()) {
3353              // call drain immediately if there are no tasks
3354              return setImmediate$1(() => q.drain());
3355          }
3356  
3357          for (var i = 0, l = data.length; i < l; i++) {
3358              var item = {
3359                  data: data[i],
3360                  priority,
3361                  callback
3362              };
3363  
3364              q._tasks.push(item);
3365          }
3366  
3367          setImmediate$1(q.process);
3368      };
3369  
3370      // Remove unshift function
3371      delete q.unshift;
3372  
3373      return q;
3374  }
3375  
3376  /**
3377   * Runs the `tasks` array of functions in parallel, without waiting until the
3378   * previous function has completed. Once any of the `tasks` complete or pass an
3379   * error to its callback, the main `callback` is immediately called. It's
3380   * equivalent to `Promise.race()`.
3381   *
3382   * @name race
3383   * @static
3384   * @memberOf module:ControlFlow
3385   * @method
3386   * @category Control Flow
3387   * @param {Array} tasks - An array containing [async functions]{@link AsyncFunction}
3388   * to run. Each function can complete with an optional `result` value.
3389   * @param {Function} callback - A callback to run once any of the functions have
3390   * completed. This function gets an error or result from the first function that
3391   * completed. Invoked with (err, result).
3392   * @returns undefined
3393   * @example
3394   *
3395   * async.race([
3396   *     function(callback) {
3397   *         setTimeout(function() {
3398   *             callback(null, 'one');
3399   *         }, 200);
3400   *     },
3401   *     function(callback) {
3402   *         setTimeout(function() {
3403   *             callback(null, 'two');
3404   *         }, 100);
3405   *     }
3406   * ],
3407   * // main callback
3408   * function(err, result) {
3409   *     // the result will be equal to 'two' as it finishes earlier
3410   * });
3411   */
3412  function race(tasks, callback) {
3413      callback = once(callback);
3414      if (!Array.isArray(tasks)) return callback(new TypeError('First argument to race must be an array of functions'));
3415      if (!tasks.length) return callback();
3416      for (var i = 0, l = tasks.length; i < l; i++) {
3417          wrapAsync(tasks[i])(callback);
3418      }
3419  }
3420  
3421  var race$1 = awaitify(race, 2);
3422  
3423  /**
3424   * Same as [`reduce`]{@link module:Collections.reduce}, only operates on `array` in reverse order.
3425   *
3426   * @name reduceRight
3427   * @static
3428   * @memberOf module:Collections
3429   * @method
3430   * @see [async.reduce]{@link module:Collections.reduce}
3431   * @alias foldr
3432   * @category Collection
3433   * @param {Array} array - A collection to iterate over.
3434   * @param {*} memo - The initial state of the reduction.
3435   * @param {AsyncFunction} iteratee - A function applied to each item in the
3436   * array to produce the next step in the reduction.
3437   * The `iteratee` should complete with the next state of the reduction.
3438   * If the iteratee complete with an error, the reduction is stopped and the
3439   * main `callback` is immediately called with the error.
3440   * Invoked with (memo, item, callback).
3441   * @param {Function} [callback] - A callback which is called after all the
3442   * `iteratee` functions have finished. Result is the reduced value. Invoked with
3443   * (err, result).
3444   * @returns {Promise} a promise, if no callback is passed
3445   */
3446  function reduceRight (array, memo, iteratee, callback) {
3447      var reversed = [...array].reverse();
3448      return reduce$1(reversed, memo, iteratee, callback);
3449  }
3450  
3451  /**
3452   * Wraps the async function in another function that always completes with a
3453   * result object, even when it errors.
3454   *
3455   * The result object has either the property `error` or `value`.
3456   *
3457   * @name reflect
3458   * @static
3459   * @memberOf module:Utils
3460   * @method
3461   * @category Util
3462   * @param {AsyncFunction} fn - The async function you want to wrap
3463   * @returns {Function} - A function that always passes null to it's callback as
3464   * the error. The second argument to the callback will be an `object` with
3465   * either an `error` or a `value` property.
3466   * @example
3467   *
3468   * async.parallel([
3469   *     async.reflect(function(callback) {
3470   *         // do some stuff ...
3471   *         callback(null, 'one');
3472   *     }),
3473   *     async.reflect(function(callback) {
3474   *         // do some more stuff but error ...
3475   *         callback('bad stuff happened');
3476   *     }),
3477   *     async.reflect(function(callback) {
3478   *         // do some more stuff ...
3479   *         callback(null, 'two');
3480   *     })
3481   * ],
3482   * // optional callback
3483   * function(err, results) {
3484   *     // values
3485   *     // results[0].value = 'one'
3486   *     // results[1].error = 'bad stuff happened'
3487   *     // results[2].value = 'two'
3488   * });
3489   */
3490  function reflect(fn) {
3491      var _fn = wrapAsync(fn);
3492      return initialParams(function reflectOn(args, reflectCallback) {
3493          args.push((error, ...cbArgs) => {
3494              let retVal = {};
3495              if (error) {
3496                  retVal.error = error;
3497              }
3498              if (cbArgs.length > 0){
3499                  var value = cbArgs;
3500                  if (cbArgs.length <= 1) {
3501                      [value] = cbArgs;
3502                  }
3503                  retVal.value = value;
3504              }
3505              reflectCallback(null, retVal);
3506          });
3507  
3508          return _fn.apply(this, args);
3509      });
3510  }
3511  
3512  /**
3513   * A helper function that wraps an array or an object of functions with `reflect`.
3514   *
3515   * @name reflectAll
3516   * @static
3517   * @memberOf module:Utils
3518   * @method
3519   * @see [async.reflect]{@link module:Utils.reflect}
3520   * @category Util
3521   * @param {Array|Object|Iterable} tasks - The collection of
3522   * [async functions]{@link AsyncFunction} to wrap in `async.reflect`.
3523   * @returns {Array} Returns an array of async functions, each wrapped in
3524   * `async.reflect`
3525   * @example
3526   *
3527   * let tasks = [
3528   *     function(callback) {
3529   *         setTimeout(function() {
3530   *             callback(null, 'one');
3531   *         }, 200);
3532   *     },
3533   *     function(callback) {
3534   *         // do some more stuff but error ...
3535   *         callback(new Error('bad stuff happened'));
3536   *     },
3537   *     function(callback) {
3538   *         setTimeout(function() {
3539   *             callback(null, 'two');
3540   *         }, 100);
3541   *     }
3542   * ];
3543   *
3544   * async.parallel(async.reflectAll(tasks),
3545   * // optional callback
3546   * function(err, results) {
3547   *     // values
3548   *     // results[0].value = 'one'
3549   *     // results[1].error = Error('bad stuff happened')
3550   *     // results[2].value = 'two'
3551   * });
3552   *
3553   * // an example using an object instead of an array
3554   * let tasks = {
3555   *     one: function(callback) {
3556   *         setTimeout(function() {
3557   *             callback(null, 'one');
3558   *         }, 200);
3559   *     },
3560   *     two: function(callback) {
3561   *         callback('two');
3562   *     },
3563   *     three: function(callback) {
3564   *         setTimeout(function() {
3565   *             callback(null, 'three');
3566   *         }, 100);
3567   *     }
3568   * };
3569   *
3570   * async.parallel(async.reflectAll(tasks),
3571   * // optional callback
3572   * function(err, results) {
3573   *     // values
3574   *     // results.one.value = 'one'
3575   *     // results.two.error = 'two'
3576   *     // results.three.value = 'three'
3577   * });
3578   */
3579  function reflectAll(tasks) {
3580      var results;
3581      if (Array.isArray(tasks)) {
3582          results = tasks.map(reflect);
3583      } else {
3584          results = {};
3585          Object.keys(tasks).forEach(key => {
3586              results[key] = reflect.call(this, tasks[key]);
3587          });
3588      }
3589      return results;
3590  }
3591  
3592  function reject(eachfn, arr, _iteratee, callback) {
3593      const iteratee = wrapAsync(_iteratee);
3594      return _filter(eachfn, arr, (value, cb) => {
3595          iteratee(value, (err, v) => {
3596              cb(err, !v);
3597          });
3598      }, callback);
3599  }
3600  
3601  /**
3602   * The opposite of [`filter`]{@link module:Collections.filter}. Removes values that pass an `async` truth test.
3603   *
3604   * @name reject
3605   * @static
3606   * @memberOf module:Collections
3607   * @method
3608   * @see [async.filter]{@link module:Collections.filter}
3609   * @category Collection
3610   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
3611   * @param {Function} iteratee - An async truth test to apply to each item in
3612   * `coll`.
3613   * The should complete with a boolean value as its `result`.
3614   * Invoked with (item, callback).
3615   * @param {Function} [callback] - A callback which is called after all the
3616   * `iteratee` functions have finished. Invoked with (err, results).
3617   * @returns {Promise} a promise, if no callback is passed
3618   * @example
3619   *
3620   * async.reject(['file1','file2','file3'], function(filePath, callback) {
3621   *     fs.access(filePath, function(err) {
3622   *         callback(null, !err)
3623   *     });
3624   * }, function(err, results) {
3625   *     // results now equals an array of missing files
3626   *     createFiles(results);
3627   * });
3628   */
3629  function reject$1 (coll, iteratee, callback) {
3630      return reject(eachOf$1, coll, iteratee, callback)
3631  }
3632  var reject$2 = awaitify(reject$1, 3);
3633  
3634  /**
3635   * The same as [`reject`]{@link module:Collections.reject} but runs a maximum of `limit` async operations at a
3636   * time.
3637   *
3638   * @name rejectLimit
3639   * @static
3640   * @memberOf module:Collections
3641   * @method
3642   * @see [async.reject]{@link module:Collections.reject}
3643   * @category Collection
3644   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
3645   * @param {number} limit - The maximum number of async operations at a time.
3646   * @param {Function} iteratee - An async truth test to apply to each item in
3647   * `coll`.
3648   * The should complete with a boolean value as its `result`.
3649   * Invoked with (item, callback).
3650   * @param {Function} [callback] - A callback which is called after all the
3651   * `iteratee` functions have finished. Invoked with (err, results).
3652   * @returns {Promise} a promise, if no callback is passed
3653   */
3654  function rejectLimit (coll, limit, iteratee, callback) {
3655      return reject(eachOfLimit(limit), coll, iteratee, callback)
3656  }
3657  var rejectLimit$1 = awaitify(rejectLimit, 4);
3658  
3659  /**
3660   * The same as [`reject`]{@link module:Collections.reject} but runs only a single async operation at a time.
3661   *
3662   * @name rejectSeries
3663   * @static
3664   * @memberOf module:Collections
3665   * @method
3666   * @see [async.reject]{@link module:Collections.reject}
3667   * @category Collection
3668   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
3669   * @param {Function} iteratee - An async truth test to apply to each item in
3670   * `coll`.
3671   * The should complete with a boolean value as its `result`.
3672   * Invoked with (item, callback).
3673   * @param {Function} [callback] - A callback which is called after all the
3674   * `iteratee` functions have finished. Invoked with (err, results).
3675   * @returns {Promise} a promise, if no callback is passed
3676   */
3677  function rejectSeries (coll, iteratee, callback) {
3678      return reject(eachOfSeries$1, coll, iteratee, callback)
3679  }
3680  var rejectSeries$1 = awaitify(rejectSeries, 3);
3681  
3682  function constant$1(value) {
3683      return function () {
3684          return value;
3685      }
3686  }
3687  
3688  /**
3689   * Attempts to get a successful response from `task` no more than `times` times
3690   * before returning an error. If the task is successful, the `callback` will be
3691   * passed the result of the successful task. If all attempts fail, the callback
3692   * will be passed the error and result (if any) of the final attempt.
3693   *
3694   * @name retry
3695   * @static
3696   * @memberOf module:ControlFlow
3697   * @method
3698   * @category Control Flow
3699   * @see [async.retryable]{@link module:ControlFlow.retryable}
3700   * @param {Object|number} [opts = {times: 5, interval: 0}| 5] - Can be either an
3701   * object with `times` and `interval` or a number.
3702   * * `times` - The number of attempts to make before giving up.  The default
3703   *   is `5`.
3704   * * `interval` - The time to wait between retries, in milliseconds.  The
3705   *   default is `0`. The interval may also be specified as a function of the
3706   *   retry count (see example).
3707   * * `errorFilter` - An optional synchronous function that is invoked on
3708   *   erroneous result. If it returns `true` the retry attempts will continue;
3709   *   if the function returns `false` the retry flow is aborted with the current
3710   *   attempt's error and result being returned to the final callback.
3711   *   Invoked with (err).
3712   * * If `opts` is a number, the number specifies the number of times to retry,
3713   *   with the default interval of `0`.
3714   * @param {AsyncFunction} task - An async function to retry.
3715   * Invoked with (callback).
3716   * @param {Function} [callback] - An optional callback which is called when the
3717   * task has succeeded, or after the final failed attempt. It receives the `err`
3718   * and `result` arguments of the last attempt at completing the `task`. Invoked
3719   * with (err, results).
3720   * @returns {Promise} a promise if no callback provided
3721   *
3722   * @example
3723   *
3724   * // The `retry` function can be used as a stand-alone control flow by passing
3725   * // a callback, as shown below:
3726   *
3727   * // try calling apiMethod 3 times
3728   * async.retry(3, apiMethod, function(err, result) {
3729   *     // do something with the result
3730   * });
3731   *
3732   * // try calling apiMethod 3 times, waiting 200 ms between each retry
3733   * async.retry({times: 3, interval: 200}, apiMethod, function(err, result) {
3734   *     // do something with the result
3735   * });
3736   *
3737   * // try calling apiMethod 10 times with exponential backoff
3738   * // (i.e. intervals of 100, 200, 400, 800, 1600, ... milliseconds)
3739   * async.retry({
3740   *   times: 10,
3741   *   interval: function(retryCount) {
3742   *     return 50 * Math.pow(2, retryCount);
3743   *   }
3744   * }, apiMethod, function(err, result) {
3745   *     // do something with the result
3746   * });
3747   *
3748   * // try calling apiMethod the default 5 times no delay between each retry
3749   * async.retry(apiMethod, function(err, result) {
3750   *     // do something with the result
3751   * });
3752   *
3753   * // try calling apiMethod only when error condition satisfies, all other
3754   * // errors will abort the retry control flow and return to final callback
3755   * async.retry({
3756   *   errorFilter: function(err) {
3757   *     return err.message === 'Temporary error'; // only retry on a specific error
3758   *   }
3759   * }, apiMethod, function(err, result) {
3760   *     // do something with the result
3761   * });
3762   *
3763   * // to retry individual methods that are not as reliable within other
3764   * // control flow functions, use the `retryable` wrapper:
3765   * async.auto({
3766   *     users: api.getUsers.bind(api),
3767   *     payments: async.retryable(3, api.getPayments.bind(api))
3768   * }, function(err, results) {
3769   *     // do something with the results
3770   * });
3771   *
3772   */
3773  const DEFAULT_TIMES = 5;
3774  const DEFAULT_INTERVAL = 0;
3775  
3776  function retry(opts, task, callback) {
3777      var options = {
3778          times: DEFAULT_TIMES,
3779          intervalFunc: constant$1(DEFAULT_INTERVAL)
3780      };
3781  
3782      if (arguments.length < 3 && typeof opts === 'function') {
3783          callback = task || promiseCallback();
3784          task = opts;
3785      } else {
3786          parseTimes(options, opts);
3787          callback = callback || promiseCallback();
3788      }
3789  
3790      if (typeof task !== 'function') {
3791          throw new Error("Invalid arguments for async.retry");
3792      }
3793  
3794      var _task = wrapAsync(task);
3795  
3796      var attempt = 1;
3797      function retryAttempt() {
3798          _task((err, ...args) => {
3799              if (err === false) return
3800              if (err && attempt++ < options.times &&
3801                  (typeof options.errorFilter != 'function' ||
3802                      options.errorFilter(err))) {
3803                  setTimeout(retryAttempt, options.intervalFunc(attempt - 1));
3804              } else {
3805                  callback(err, ...args);
3806              }
3807          });
3808      }
3809  
3810      retryAttempt();
3811      return callback[PROMISE_SYMBOL]
3812  }
3813  
3814  function parseTimes(acc, t) {
3815      if (typeof t === 'object') {
3816          acc.times = +t.times || DEFAULT_TIMES;
3817  
3818          acc.intervalFunc = typeof t.interval === 'function' ?
3819              t.interval :
3820              constant$1(+t.interval || DEFAULT_INTERVAL);
3821  
3822          acc.errorFilter = t.errorFilter;
3823      } else if (typeof t === 'number' || typeof t === 'string') {
3824          acc.times = +t || DEFAULT_TIMES;
3825      } else {
3826          throw new Error("Invalid arguments for async.retry");
3827      }
3828  }
3829  
3830  /**
3831   * A close relative of [`retry`]{@link module:ControlFlow.retry}.  This method
3832   * wraps a task and makes it retryable, rather than immediately calling it
3833   * with retries.
3834   *
3835   * @name retryable
3836   * @static
3837   * @memberOf module:ControlFlow
3838   * @method
3839   * @see [async.retry]{@link module:ControlFlow.retry}
3840   * @category Control Flow
3841   * @param {Object|number} [opts = {times: 5, interval: 0}| 5] - optional
3842   * options, exactly the same as from `retry`, except for a `opts.arity` that
3843   * is the arity of the `task` function, defaulting to `task.length`
3844   * @param {AsyncFunction} task - the asynchronous function to wrap.
3845   * This function will be passed any arguments passed to the returned wrapper.
3846   * Invoked with (...args, callback).
3847   * @returns {AsyncFunction} The wrapped function, which when invoked, will
3848   * retry on an error, based on the parameters specified in `opts`.
3849   * This function will accept the same parameters as `task`.
3850   * @example
3851   *
3852   * async.auto({
3853   *     dep1: async.retryable(3, getFromFlakyService),
3854   *     process: ["dep1", async.retryable(3, function (results, cb) {
3855   *         maybeProcessData(results.dep1, cb);
3856   *     })]
3857   * }, callback);
3858   */
3859  function retryable (opts, task) {
3860      if (!task) {
3861          task = opts;
3862          opts = null;
3863      }
3864      let arity = (opts && opts.arity) || task.length;
3865      if (isAsync(task)) {
3866          arity += 1;
3867      }
3868      var _task = wrapAsync(task);
3869      return initialParams((args, callback) => {
3870          if (args.length < arity - 1 || callback == null) {
3871              args.push(callback);
3872              callback = promiseCallback();
3873          }
3874          function taskFn(cb) {
3875              _task(...args, cb);
3876          }
3877  
3878          if (opts) retry(opts, taskFn, callback);
3879          else retry(taskFn, callback);
3880  
3881          return callback[PROMISE_SYMBOL]
3882      });
3883  }
3884  
3885  /**
3886   * Run the functions in the `tasks` collection in series, each one running once
3887   * the previous function has completed. If any functions in the series pass an
3888   * error to its callback, no more functions are run, and `callback` is
3889   * immediately called with the value of the error. Otherwise, `callback`
3890   * receives an array of results when `tasks` have completed.
3891   *
3892   * It is also possible to use an object instead of an array. Each property will
3893   * be run as a function, and the results will be passed to the final `callback`
3894   * as an object instead of an array. This can be a more readable way of handling
3895   *  results from {@link async.series}.
3896   *
3897   * **Note** that while many implementations preserve the order of object
3898   * properties, the [ECMAScript Language Specification](http://www.ecma-international.org/ecma-262/5.1/#sec-8.6)
3899   * explicitly states that
3900   *
3901   * > The mechanics and order of enumerating the properties is not specified.
3902   *
3903   * So if you rely on the order in which your series of functions are executed,
3904   * and want this to work on all platforms, consider using an array.
3905   *
3906   * @name series
3907   * @static
3908   * @memberOf module:ControlFlow
3909   * @method
3910   * @category Control Flow
3911   * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection containing
3912   * [async functions]{@link AsyncFunction} to run in series.
3913   * Each function can complete with any number of optional `result` values.
3914   * @param {Function} [callback] - An optional callback to run once all the
3915   * functions have completed. This function gets a results array (or object)
3916   * containing all the result arguments passed to the `task` callbacks. Invoked
3917   * with (err, result).
3918   * @return {Promise} a promise, if no callback is passed
3919   * @example
3920   * async.series([
3921   *     function(callback) {
3922   *         // do some stuff ...
3923   *         callback(null, 'one');
3924   *     },
3925   *     function(callback) {
3926   *         // do some more stuff ...
3927   *         callback(null, 'two');
3928   *     }
3929   * ],
3930   * // optional callback
3931   * function(err, results) {
3932   *     // results is now equal to ['one', 'two']
3933   * });
3934   *
3935   * async.series({
3936   *     one: function(callback) {
3937   *         setTimeout(function() {
3938   *             callback(null, 1);
3939   *         }, 200);
3940   *     },
3941   *     two: function(callback){
3942   *         setTimeout(function() {
3943   *             callback(null, 2);
3944   *         }, 100);
3945   *     }
3946   * }, function(err, results) {
3947   *     // results is now equal to: {one: 1, two: 2}
3948   * });
3949   */
3950  function series(tasks, callback) {
3951      return _parallel(eachOfSeries$1, tasks, callback);
3952  }
3953  
3954  /**
3955   * Returns `true` if at least one element in the `coll` satisfies an async test.
3956   * If any iteratee call returns `true`, the main `callback` is immediately
3957   * called.
3958   *
3959   * @name some
3960   * @static
3961   * @memberOf module:Collections
3962   * @method
3963   * @alias any
3964   * @category Collection
3965   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
3966   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
3967   * in the collections in parallel.
3968   * The iteratee should complete with a boolean `result` value.
3969   * Invoked with (item, callback).
3970   * @param {Function} [callback] - A callback which is called as soon as any
3971   * iteratee returns `true`, or after all the iteratee functions have finished.
3972   * Result will be either `true` or `false` depending on the values of the async
3973   * tests. Invoked with (err, result).
3974   * @returns {Promise} a promise, if no callback provided
3975   * @example
3976   *
3977   * async.some(['file1','file2','file3'], function(filePath, callback) {
3978   *     fs.access(filePath, function(err) {
3979   *         callback(null, !err)
3980   *     });
3981   * }, function(err, result) {
3982   *     // if result is true then at least one of the files exists
3983   * });
3984   */
3985  function some(coll, iteratee, callback) {
3986      return _createTester(Boolean, res => res)(eachOf$1, coll, iteratee, callback)
3987  }
3988  var some$1 = awaitify(some, 3);
3989  
3990  /**
3991   * The same as [`some`]{@link module:Collections.some} but runs a maximum of `limit` async operations at a time.
3992   *
3993   * @name someLimit
3994   * @static
3995   * @memberOf module:Collections
3996   * @method
3997   * @see [async.some]{@link module:Collections.some}
3998   * @alias anyLimit
3999   * @category Collection
4000   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
4001   * @param {number} limit - The maximum number of async operations at a time.
4002   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
4003   * in the collections in parallel.
4004   * The iteratee should complete with a boolean `result` value.
4005   * Invoked with (item, callback).
4006   * @param {Function} [callback] - A callback which is called as soon as any
4007   * iteratee returns `true`, or after all the iteratee functions have finished.
4008   * Result will be either `true` or `false` depending on the values of the async
4009   * tests. Invoked with (err, result).
4010   * @returns {Promise} a promise, if no callback provided
4011   */
4012  function someLimit(coll, limit, iteratee, callback) {
4013      return _createTester(Boolean, res => res)(eachOfLimit(limit), coll, iteratee, callback)
4014  }
4015  var someLimit$1 = awaitify(someLimit, 4);
4016  
4017  /**
4018   * The same as [`some`]{@link module:Collections.some} but runs only a single async operation at a time.
4019   *
4020   * @name someSeries
4021   * @static
4022   * @memberOf module:Collections
4023   * @method
4024   * @see [async.some]{@link module:Collections.some}
4025   * @alias anySeries
4026   * @category Collection
4027   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
4028   * @param {AsyncFunction} iteratee - An async truth test to apply to each item
4029   * in the collections in series.
4030   * The iteratee should complete with a boolean `result` value.
4031   * Invoked with (item, callback).
4032   * @param {Function} [callback] - A callback which is called as soon as any
4033   * iteratee returns `true`, or after all the iteratee functions have finished.
4034   * Result will be either `true` or `false` depending on the values of the async
4035   * tests. Invoked with (err, result).
4036   * @returns {Promise} a promise, if no callback provided
4037   */
4038  function someSeries(coll, iteratee, callback) {
4039      return _createTester(Boolean, res => res)(eachOfSeries$1, coll, iteratee, callback)
4040  }
4041  var someSeries$1 = awaitify(someSeries, 3);
4042  
4043  /**
4044   * Sorts a list by the results of running each `coll` value through an async
4045   * `iteratee`.
4046   *
4047   * @name sortBy
4048   * @static
4049   * @memberOf module:Collections
4050   * @method
4051   * @category Collection
4052   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
4053   * @param {AsyncFunction} iteratee - An async function to apply to each item in
4054   * `coll`.
4055   * The iteratee should complete with a value to use as the sort criteria as
4056   * its `result`.
4057   * Invoked with (item, callback).
4058   * @param {Function} callback - A callback which is called after all the
4059   * `iteratee` functions have finished, or an error occurs. Results is the items
4060   * from the original `coll` sorted by the values returned by the `iteratee`
4061   * calls. Invoked with (err, results).
4062   * @returns {Promise} a promise, if no callback passed
4063   * @example
4064   *
4065   * async.sortBy(['file1','file2','file3'], function(file, callback) {
4066   *     fs.stat(file, function(err, stats) {
4067   *         callback(err, stats.mtime);
4068   *     });
4069   * }, function(err, results) {
4070   *     // results is now the original array of files sorted by
4071   *     // modified date
4072   * });
4073   *
4074   * // By modifying the callback parameter the
4075   * // sorting order can be influenced:
4076   *
4077   * // ascending order
4078   * async.sortBy([1,9,3,5], function(x, callback) {
4079   *     callback(null, x);
4080   * }, function(err,result) {
4081   *     // result callback
4082   * });
4083   *
4084   * // descending order
4085   * async.sortBy([1,9,3,5], function(x, callback) {
4086   *     callback(null, x*-1);    //<- x*-1 instead of x, turns the order around
4087   * }, function(err,result) {
4088   *     // result callback
4089   * });
4090   */
4091  function sortBy (coll, iteratee, callback) {
4092      var _iteratee = wrapAsync(iteratee);
4093      return map$1(coll, (x, iterCb) => {
4094          _iteratee(x, (err, criteria) => {
4095              if (err) return iterCb(err);
4096              iterCb(err, {value: x, criteria});
4097          });
4098      }, (err, results) => {
4099          if (err) return callback(err);
4100          callback(null, results.sort(comparator).map(v => v.value));
4101      });
4102  
4103      function comparator(left, right) {
4104          var a = left.criteria, b = right.criteria;
4105          return a < b ? -1 : a > b ? 1 : 0;
4106      }
4107  }
4108  var sortBy$1 = awaitify(sortBy, 3);
4109  
4110  /**
4111   * Sets a time limit on an asynchronous function. If the function does not call
4112   * its callback within the specified milliseconds, it will be called with a
4113   * timeout error. The code property for the error object will be `'ETIMEDOUT'`.
4114   *
4115   * @name timeout
4116   * @static
4117   * @memberOf module:Utils
4118   * @method
4119   * @category Util
4120   * @param {AsyncFunction} asyncFn - The async function to limit in time.
4121   * @param {number} milliseconds - The specified time limit.
4122   * @param {*} [info] - Any variable you want attached (`string`, `object`, etc)
4123   * to timeout Error for more information..
4124   * @returns {AsyncFunction} Returns a wrapped function that can be used with any
4125   * of the control flow functions.
4126   * Invoke this function with the same parameters as you would `asyncFunc`.
4127   * @example
4128   *
4129   * function myFunction(foo, callback) {
4130   *     doAsyncTask(foo, function(err, data) {
4131   *         // handle errors
4132   *         if (err) return callback(err);
4133   *
4134   *         // do some stuff ...
4135   *
4136   *         // return processed data
4137   *         return callback(null, data);
4138   *     });
4139   * }
4140   *
4141   * var wrapped = async.timeout(myFunction, 1000);
4142   *
4143   * // call `wrapped` as you would `myFunction`
4144   * wrapped({ bar: 'bar' }, function(err, data) {
4145   *     // if `myFunction` takes < 1000 ms to execute, `err`
4146   *     // and `data` will have their expected values
4147   *
4148   *     // else `err` will be an Error with the code 'ETIMEDOUT'
4149   * });
4150   */
4151  function timeout(asyncFn, milliseconds, info) {
4152      var fn = wrapAsync(asyncFn);
4153  
4154      return initialParams((args, callback) => {
4155          var timedOut = false;
4156          var timer;
4157  
4158          function timeoutCallback() {
4159              var name = asyncFn.name || 'anonymous';
4160              var error  = new Error('Callback function "' + name + '" timed out.');
4161              error.code = 'ETIMEDOUT';
4162              if (info) {
4163                  error.info = info;
4164              }
4165              timedOut = true;
4166              callback(error);
4167          }
4168  
4169          args.push((...cbArgs) => {
4170              if (!timedOut) {
4171                  callback(...cbArgs);
4172                  clearTimeout(timer);
4173              }
4174          });
4175  
4176          // setup timer and call original function
4177          timer = setTimeout(timeoutCallback, milliseconds);
4178          fn(...args);
4179      });
4180  }
4181  
4182  function range(size) {
4183      var result = Array(size);
4184      while (size--) {
4185          result[size] = size;
4186      }
4187      return result;
4188  }
4189  
4190  /**
4191   * The same as [times]{@link module:ControlFlow.times} but runs a maximum of `limit` async operations at a
4192   * time.
4193   *
4194   * @name timesLimit
4195   * @static
4196   * @memberOf module:ControlFlow
4197   * @method
4198   * @see [async.times]{@link module:ControlFlow.times}
4199   * @category Control Flow
4200   * @param {number} count - The number of times to run the function.
4201   * @param {number} limit - The maximum number of async operations at a time.
4202   * @param {AsyncFunction} iteratee - The async function to call `n` times.
4203   * Invoked with the iteration index and a callback: (n, next).
4204   * @param {Function} callback - see [async.map]{@link module:Collections.map}.
4205   * @returns {Promise} a promise, if no callback is provided
4206   */
4207  function timesLimit(count, limit, iteratee, callback) {
4208      var _iteratee = wrapAsync(iteratee);
4209      return mapLimit$1(range(count), limit, _iteratee, callback);
4210  }
4211  
4212  /**
4213   * Calls the `iteratee` function `n` times, and accumulates results in the same
4214   * manner you would use with [map]{@link module:Collections.map}.
4215   *
4216   * @name times
4217   * @static
4218   * @memberOf module:ControlFlow
4219   * @method
4220   * @see [async.map]{@link module:Collections.map}
4221   * @category Control Flow
4222   * @param {number} n - The number of times to run the function.
4223   * @param {AsyncFunction} iteratee - The async function to call `n` times.
4224   * Invoked with the iteration index and a callback: (n, next).
4225   * @param {Function} callback - see {@link module:Collections.map}.
4226   * @returns {Promise} a promise, if no callback is provided
4227   * @example
4228   *
4229   * // Pretend this is some complicated async factory
4230   * var createUser = function(id, callback) {
4231   *     callback(null, {
4232   *         id: 'user' + id
4233   *     });
4234   * };
4235   *
4236   * // generate 5 users
4237   * async.times(5, function(n, next) {
4238   *     createUser(n, function(err, user) {
4239   *         next(err, user);
4240   *     });
4241   * }, function(err, users) {
4242   *     // we should now have 5 users
4243   * });
4244   */
4245  function times (n, iteratee, callback) {
4246      return timesLimit(n, Infinity, iteratee, callback)
4247  }
4248  
4249  /**
4250   * The same as [times]{@link module:ControlFlow.times} but runs only a single async operation at a time.
4251   *
4252   * @name timesSeries
4253   * @static
4254   * @memberOf module:ControlFlow
4255   * @method
4256   * @see [async.times]{@link module:ControlFlow.times}
4257   * @category Control Flow
4258   * @param {number} n - The number of times to run the function.
4259   * @param {AsyncFunction} iteratee - The async function to call `n` times.
4260   * Invoked with the iteration index and a callback: (n, next).
4261   * @param {Function} callback - see {@link module:Collections.map}.
4262   * @returns {Promise} a promise, if no callback is provided
4263   */
4264  function timesSeries (n, iteratee, callback) {
4265      return timesLimit(n, 1, iteratee, callback)
4266  }
4267  
4268  /**
4269   * A relative of `reduce`.  Takes an Object or Array, and iterates over each
4270   * element in parallel, each step potentially mutating an `accumulator` value.
4271   * The type of the accumulator defaults to the type of collection passed in.
4272   *
4273   * @name transform
4274   * @static
4275   * @memberOf module:Collections
4276   * @method
4277   * @category Collection
4278   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
4279   * @param {*} [accumulator] - The initial state of the transform.  If omitted,
4280   * it will default to an empty Object or Array, depending on the type of `coll`
4281   * @param {AsyncFunction} iteratee - A function applied to each item in the
4282   * collection that potentially modifies the accumulator.
4283   * Invoked with (accumulator, item, key, callback).
4284   * @param {Function} [callback] - A callback which is called after all the
4285   * `iteratee` functions have finished. Result is the transformed accumulator.
4286   * Invoked with (err, result).
4287   * @returns {Promise} a promise, if no callback provided
4288   * @example
4289   *
4290   * async.transform([1,2,3], function(acc, item, index, callback) {
4291   *     // pointless async:
4292   *     process.nextTick(function() {
4293   *         acc[index] = item * 2
4294   *         callback(null)
4295   *     });
4296   * }, function(err, result) {
4297   *     // result is now equal to [2, 4, 6]
4298   * });
4299   *
4300   * @example
4301   *
4302   * async.transform({a: 1, b: 2, c: 3}, function (obj, val, key, callback) {
4303   *     setImmediate(function () {
4304   *         obj[key] = val * 2;
4305   *         callback();
4306   *     })
4307   * }, function (err, result) {
4308   *     // result is equal to {a: 2, b: 4, c: 6}
4309   * })
4310   */
4311  function transform (coll, accumulator, iteratee, callback) {
4312      if (arguments.length <= 3 && typeof accumulator === 'function') {
4313          callback = iteratee;
4314          iteratee = accumulator;
4315          accumulator = Array.isArray(coll) ? [] : {};
4316      }
4317      callback = once(callback || promiseCallback());
4318      var _iteratee = wrapAsync(iteratee);
4319  
4320      eachOf$1(coll, (v, k, cb) => {
4321          _iteratee(accumulator, v, k, cb);
4322      }, err => callback(err, accumulator));
4323      return callback[PROMISE_SYMBOL]
4324  }
4325  
4326  /**
4327   * It runs each task in series but stops whenever any of the functions were
4328   * successful. If one of the tasks were successful, the `callback` will be
4329   * passed the result of the successful task. If all tasks fail, the callback
4330   * will be passed the error and result (if any) of the final attempt.
4331   *
4332   * @name tryEach
4333   * @static
4334   * @memberOf module:ControlFlow
4335   * @method
4336   * @category Control Flow
4337   * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection containing functions to
4338   * run, each function is passed a `callback(err, result)` it must call on
4339   * completion with an error `err` (which can be `null`) and an optional `result`
4340   * value.
4341   * @param {Function} [callback] - An optional callback which is called when one
4342   * of the tasks has succeeded, or all have failed. It receives the `err` and
4343   * `result` arguments of the last attempt at completing the `task`. Invoked with
4344   * (err, results).
4345   * @returns {Promise} a promise, if no callback is passed
4346   * @example
4347   * async.tryEach([
4348   *     function getDataFromFirstWebsite(callback) {
4349   *         // Try getting the data from the first website
4350   *         callback(err, data);
4351   *     },
4352   *     function getDataFromSecondWebsite(callback) {
4353   *         // First website failed,
4354   *         // Try getting the data from the backup website
4355   *         callback(err, data);
4356   *     }
4357   * ],
4358   * // optional callback
4359   * function(err, results) {
4360   *     Now do something with the data.
4361   * });
4362   *
4363   */
4364  function tryEach(tasks, callback) {
4365      var error = null;
4366      var result;
4367      return eachSeries$1(tasks, (task, taskCb) => {
4368          wrapAsync(task)((err, ...args) => {
4369              if (err === false) return taskCb(err);
4370  
4371              if (args.length < 2) {
4372                  [result] = args;
4373              } else {
4374                  result = args;
4375              }
4376              error = err;
4377              taskCb(err ? null : {});
4378          });
4379      }, () => callback(error, result));
4380  }
4381  
4382  var tryEach$1 = awaitify(tryEach);
4383  
4384  /**
4385   * Undoes a [memoize]{@link module:Utils.memoize}d function, reverting it to the original,
4386   * unmemoized form. Handy for testing.
4387   *
4388   * @name unmemoize
4389   * @static
4390   * @memberOf module:Utils
4391   * @method
4392   * @see [async.memoize]{@link module:Utils.memoize}
4393   * @category Util
4394   * @param {AsyncFunction} fn - the memoized function
4395   * @returns {AsyncFunction} a function that calls the original unmemoized function
4396   */
4397  function unmemoize(fn) {
4398      return (...args) => {
4399          return (fn.unmemoized || fn)(...args);
4400      };
4401  }
4402  
4403  /**
4404   * Repeatedly call `iteratee`, while `test` returns `true`. Calls `callback` when
4405   * stopped, or an error occurs.
4406   *
4407   * @name whilst
4408   * @static
4409   * @memberOf module:ControlFlow
4410   * @method
4411   * @category Control Flow
4412   * @param {AsyncFunction} test - asynchronous truth test to perform before each
4413   * execution of `iteratee`. Invoked with ().
4414   * @param {AsyncFunction} iteratee - An async function which is called each time
4415   * `test` passes. Invoked with (callback).
4416   * @param {Function} [callback] - A callback which is called after the test
4417   * function has failed and repeated execution of `iteratee` has stopped. `callback`
4418   * will be passed an error and any arguments passed to the final `iteratee`'s
4419   * callback. Invoked with (err, [results]);
4420   * @returns {Promise} a promise, if no callback is passed
4421   * @example
4422   *
4423   * var count = 0;
4424   * async.whilst(
4425   *     function test(cb) { cb(null, count < 5); },
4426   *     function iter(callback) {
4427   *         count++;
4428   *         setTimeout(function() {
4429   *             callback(null, count);
4430   *         }, 1000);
4431   *     },
4432   *     function (err, n) {
4433   *         // 5 seconds have passed, n = 5
4434   *     }
4435   * );
4436   */
4437  function whilst(test, iteratee, callback) {
4438      callback = onlyOnce(callback);
4439      var _fn = wrapAsync(iteratee);
4440      var _test = wrapAsync(test);
4441      var results = [];
4442  
4443      function next(err, ...rest) {
4444          if (err) return callback(err);
4445          results = rest;
4446          if (err === false) return;
4447          _test(check);
4448      }
4449  
4450      function check(err, truth) {
4451          if (err) return callback(err);
4452          if (err === false) return;
4453          if (!truth) return callback(null, ...results);
4454          _fn(next);
4455      }
4456  
4457      return _test(check);
4458  }
4459  var whilst$1 = awaitify(whilst, 3);
4460  
4461  /**
4462   * Repeatedly call `iteratee` until `test` returns `true`. Calls `callback` when
4463   * stopped, or an error occurs. `callback` will be passed an error and any
4464   * arguments passed to the final `iteratee`'s callback.
4465   *
4466   * The inverse of [whilst]{@link module:ControlFlow.whilst}.
4467   *
4468   * @name until
4469   * @static
4470   * @memberOf module:ControlFlow
4471   * @method
4472   * @see [async.whilst]{@link module:ControlFlow.whilst}
4473   * @category Control Flow
4474   * @param {AsyncFunction} test - asynchronous truth test to perform before each
4475   * execution of `iteratee`. Invoked with (callback).
4476   * @param {AsyncFunction} iteratee - An async function which is called each time
4477   * `test` fails. Invoked with (callback).
4478   * @param {Function} [callback] - A callback which is called after the test
4479   * function has passed and repeated execution of `iteratee` has stopped. `callback`
4480   * will be passed an error and any arguments passed to the final `iteratee`'s
4481   * callback. Invoked with (err, [results]);
4482   * @returns {Promise} a promise, if a callback is not passed
4483   *
4484   * @example
4485   * const results = []
4486   * let finished = false
4487   * async.until(function test(page, cb) {
4488   *     cb(null, finished)
4489   * }, function iter(next) {
4490   *     fetchPage(url, (err, body) => {
4491   *         if (err) return next(err)
4492   *         results = results.concat(body.objects)
4493   *         finished = !!body.next
4494   *         next(err)
4495   *     })
4496   * }, function done (err) {
4497   *     // all pages have been fetched
4498   * })
4499   */
4500  function until(test, iteratee, callback) {
4501      const _test = wrapAsync(test);
4502      return whilst$1((cb) => _test((err, truth) => cb (err, !truth)), iteratee, callback);
4503  }
4504  
4505  /**
4506   * Runs the `tasks` array of functions in series, each passing their results to
4507   * the next in the array. However, if any of the `tasks` pass an error to their
4508   * own callback, the next function is not executed, and the main `callback` is
4509   * immediately called with the error.
4510   *
4511   * @name waterfall
4512   * @static
4513   * @memberOf module:ControlFlow
4514   * @method
4515   * @category Control Flow
4516   * @param {Array} tasks - An array of [async functions]{@link AsyncFunction}
4517   * to run.
4518   * Each function should complete with any number of `result` values.
4519   * The `result` values will be passed as arguments, in order, to the next task.
4520   * @param {Function} [callback] - An optional callback to run once all the
4521   * functions have completed. This will be passed the results of the last task's
4522   * callback. Invoked with (err, [results]).
4523   * @returns undefined
4524   * @example
4525   *
4526   * async.waterfall([
4527   *     function(callback) {
4528   *         callback(null, 'one', 'two');
4529   *     },
4530   *     function(arg1, arg2, callback) {
4531   *         // arg1 now equals 'one' and arg2 now equals 'two'
4532   *         callback(null, 'three');
4533   *     },
4534   *     function(arg1, callback) {
4535   *         // arg1 now equals 'three'
4536   *         callback(null, 'done');
4537   *     }
4538   * ], function (err, result) {
4539   *     // result now equals 'done'
4540   * });
4541   *
4542   * // Or, with named functions:
4543   * async.waterfall([
4544   *     myFirstFunction,
4545   *     mySecondFunction,
4546   *     myLastFunction,
4547   * ], function (err, result) {
4548   *     // result now equals 'done'
4549   * });
4550   * function myFirstFunction(callback) {
4551   *     callback(null, 'one', 'two');
4552   * }
4553   * function mySecondFunction(arg1, arg2, callback) {
4554   *     // arg1 now equals 'one' and arg2 now equals 'two'
4555   *     callback(null, 'three');
4556   * }
4557   * function myLastFunction(arg1, callback) {
4558   *     // arg1 now equals 'three'
4559   *     callback(null, 'done');
4560   * }
4561   */
4562  function waterfall (tasks, callback) {
4563      callback = once(callback);
4564      if (!Array.isArray(tasks)) return callback(new Error('First argument to waterfall must be an array of functions'));
4565      if (!tasks.length) return callback();
4566      var taskIndex = 0;
4567  
4568      function nextTask(args) {
4569          var task = wrapAsync(tasks[taskIndex++]);
4570          task(...args, onlyOnce(next));
4571      }
4572  
4573      function next(err, ...args) {
4574          if (err === false) return
4575          if (err || taskIndex === tasks.length) {
4576              return callback(err, ...args);
4577          }
4578          nextTask(args);
4579      }
4580  
4581      nextTask([]);
4582  }
4583  
4584  var waterfall$1 = awaitify(waterfall);
4585  
4586  /**
4587   * An "async function" in the context of Async is an asynchronous function with
4588   * a variable number of parameters, with the final parameter being a callback.
4589   * (`function (arg1, arg2, ..., callback) {}`)
4590   * The final callback is of the form `callback(err, results...)`, which must be
4591   * called once the function is completed.  The callback should be called with a
4592   * Error as its first argument to signal that an error occurred.
4593   * Otherwise, if no error occurred, it should be called with `null` as the first
4594   * argument, and any additional `result` arguments that may apply, to signal
4595   * successful completion.
4596   * The callback must be called exactly once, ideally on a later tick of the
4597   * JavaScript event loop.
4598   *
4599   * This type of function is also referred to as a "Node-style async function",
4600   * or a "continuation passing-style function" (CPS). Most of the methods of this
4601   * library are themselves CPS/Node-style async functions, or functions that
4602   * return CPS/Node-style async functions.
4603   *
4604   * Wherever we accept a Node-style async function, we also directly accept an
4605   * [ES2017 `async` function]{@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function}.
4606   * In this case, the `async` function will not be passed a final callback
4607   * argument, and any thrown error will be used as the `err` argument of the
4608   * implicit callback, and the return value will be used as the `result` value.
4609   * (i.e. a `rejected` of the returned Promise becomes the `err` callback
4610   * argument, and a `resolved` value becomes the `result`.)
4611   *
4612   * Note, due to JavaScript limitations, we can only detect native `async`
4613   * functions and not transpilied implementations.
4614   * Your environment must have `async`/`await` support for this to work.
4615   * (e.g. Node > v7.6, or a recent version of a modern browser).
4616   * If you are using `async` functions through a transpiler (e.g. Babel), you
4617   * must still wrap the function with [asyncify]{@link module:Utils.asyncify},
4618   * because the `async function` will be compiled to an ordinary function that
4619   * returns a promise.
4620   *
4621   * @typedef {Function} AsyncFunction
4622   * @static
4623   */
4624  
4625  var index = {
4626      apply,
4627      applyEach: applyEach$1,
4628      applyEachSeries,
4629      asyncify,
4630      auto,
4631      autoInject,
4632      cargo,
4633      cargoQueue: cargo$1,
4634      compose,
4635      concat: concat$1,
4636      concatLimit: concatLimit$1,
4637      concatSeries: concatSeries$1,
4638      constant,
4639      detect: detect$1,
4640      detectLimit: detectLimit$1,
4641      detectSeries: detectSeries$1,
4642      dir,
4643      doUntil,
4644      doWhilst: doWhilst$1,
4645      each,
4646      eachLimit: eachLimit$2,
4647      eachOf: eachOf$1,
4648      eachOfLimit: eachOfLimit$2,
4649      eachOfSeries: eachOfSeries$1,
4650      eachSeries: eachSeries$1,
4651      ensureAsync,
4652      every: every$1,
4653      everyLimit: everyLimit$1,
4654      everySeries: everySeries$1,
4655      filter: filter$1,
4656      filterLimit: filterLimit$1,
4657      filterSeries: filterSeries$1,
4658      forever: forever$1,
4659      groupBy,
4660      groupByLimit: groupByLimit$1,
4661      groupBySeries,
4662      log,
4663      map: map$1,
4664      mapLimit: mapLimit$1,
4665      mapSeries: mapSeries$1,
4666      mapValues,
4667      mapValuesLimit: mapValuesLimit$1,
4668      mapValuesSeries,
4669      memoize,
4670      nextTick,
4671      parallel,
4672      parallelLimit,
4673      priorityQueue,
4674      queue: queue$1,
4675      race: race$1,
4676      reduce: reduce$1,
4677      reduceRight,
4678      reflect,
4679      reflectAll,
4680      reject: reject$2,
4681      rejectLimit: rejectLimit$1,
4682      rejectSeries: rejectSeries$1,
4683      retry,
4684      retryable,
4685      seq,
4686      series,
4687      setImmediate: setImmediate$1,
4688      some: some$1,
4689      someLimit: someLimit$1,
4690      someSeries: someSeries$1,
4691      sortBy: sortBy$1,
4692      timeout,
4693      times,
4694      timesLimit,
4695      timesSeries,
4696      transform,
4697      tryEach: tryEach$1,
4698      unmemoize,
4699      until,
4700      waterfall: waterfall$1,
4701      whilst: whilst$1,
4702  
4703      // aliases
4704      all: every$1,
4705      allLimit: everyLimit$1,
4706      allSeries: everySeries$1,
4707      any: some$1,
4708      anyLimit: someLimit$1,
4709      anySeries: someSeries$1,
4710      find: detect$1,
4711      findLimit: detectLimit$1,
4712      findSeries: detectSeries$1,
4713      flatMap: concat$1,
4714      flatMapLimit: concatLimit$1,
4715      flatMapSeries: concatSeries$1,
4716      forEach: each,
4717      forEachSeries: eachSeries$1,
4718      forEachLimit: eachLimit$2,
4719      forEachOf: eachOf$1,
4720      forEachOfSeries: eachOfSeries$1,
4721      forEachOfLimit: eachOfLimit$2,
4722      inject: reduce$1,
4723      foldl: reduce$1,
4724      foldr: reduceRight,
4725      select: filter$1,
4726      selectLimit: filterLimit$1,
4727      selectSeries: filterSeries$1,
4728      wrapSync: asyncify,
4729      during: whilst$1,
4730      doDuring: doWhilst$1
4731  };
4732  
4733  export default index;
4734  export { apply, applyEach$1 as applyEach, applyEachSeries, asyncify, auto, autoInject, cargo, cargo$1 as cargoQueue, compose, concat$1 as concat, concatLimit$1 as concatLimit, concatSeries$1 as concatSeries, constant, detect$1 as detect, detectLimit$1 as detectLimit, detectSeries$1 as detectSeries, dir, doUntil, doWhilst$1 as doWhilst, each, eachLimit$2 as eachLimit, eachOf$1 as eachOf, eachOfLimit$2 as eachOfLimit, eachOfSeries$1 as eachOfSeries, eachSeries$1 as eachSeries, ensureAsync, every$1 as every, everyLimit$1 as everyLimit, everySeries$1 as everySeries, filter$1 as filter, filterLimit$1 as filterLimit, filterSeries$1 as filterSeries, forever$1 as forever, groupBy, groupByLimit$1 as groupByLimit, groupBySeries, log, map$1 as map, mapLimit$1 as mapLimit, mapSeries$1 as mapSeries, mapValues, mapValuesLimit$1 as mapValuesLimit, mapValuesSeries, memoize, nextTick, parallel, parallelLimit, priorityQueue, queue$1 as queue, race$1 as race, reduce$1 as reduce, reduceRight, reflect, reflectAll, reject$2 as reject, rejectLimit$1 as rejectLimit, rejectSeries$1 as rejectSeries, retry, retryable, seq, series, setImmediate$1 as setImmediate, some$1 as some, someLimit$1 as someLimit, someSeries$1 as someSeries, sortBy$1 as sortBy, timeout, times, timesLimit, timesSeries, transform, tryEach$1 as tryEach, unmemoize, until, waterfall$1 as waterfall, whilst$1 as whilst, every$1 as all, everyLimit$1 as allLimit, everySeries$1 as allSeries, some$1 as any, someLimit$1 as anyLimit, someSeries$1 as anySeries, detect$1 as find, detectLimit$1 as findLimit, detectSeries$1 as findSeries, concat$1 as flatMap, concatLimit$1 as flatMapLimit, concatSeries$1 as flatMapSeries, each as forEach, eachSeries$1 as forEachSeries, eachLimit$2 as forEachLimit, eachOf$1 as forEachOf, eachOfSeries$1 as forEachOfSeries, eachOfLimit$2 as forEachOfLimit, reduce$1 as inject, reduce$1 as foldl, reduceRight as foldr, filter$1 as select, filterLimit$1 as selectLimit, filterSeries$1 as selectSeries, asyncify as wrapSync, whilst$1 as during, doWhilst$1 as doDuring };