1  'use strict';
 2  
 3  Object.defineProperty(exports, "__esModule", {
 4      value: true
 5  });
 6  
 7  var _mapLimit = require('./mapLimit');
 8  
 9  var _mapLimit2 = _interopRequireDefault(_mapLimit);
10  
11  var _wrapAsync = require('./internal/wrapAsync');
12  
13  var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
14  
15  var _awaitify = require('./internal/awaitify');
16  
17  var _awaitify2 = _interopRequireDefault(_awaitify);
18  
19  function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
20  
21  /**
22   * The same as [`groupBy`]{@link module:Collections.groupBy} but runs a maximum of `limit` async operations at a time.
23   *
24   * @name groupByLimit
25   * @static
26   * @memberOf module:Collections
27   * @method
28   * @see [async.groupBy]{@link module:Collections.groupBy}
29   * @category Collection
30   * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
31   * @param {number} limit - The maximum number of async operations at a time.
32   * @param {AsyncFunction} iteratee - An async function to apply to each item in
33   * `coll`.
34   * The iteratee should complete with a `key` to group the value under.
35   * Invoked with (value, callback).
36   * @param {Function} [callback] - A callback which is called when all `iteratee`
37   * functions have finished, or an error occurs. Result is an `Object` whoses
38   * properties are arrays of values which returned the corresponding key.
39   * @returns {Promise} a promise, if no callback is passed
40   */
41  function groupByLimit(coll, limit, iteratee, callback) {
42      var _iteratee = (0, _wrapAsync2.default)(iteratee);
43      return (0, _mapLimit2.default)(coll, limit, (val, iterCb) => {
44          _iteratee(val, (err, key) => {
45              if (err) return iterCb(err);
46              return iterCb(err, { key, val });
47          });
48      }, (err, mapResults) => {
49          var result = {};
50          // from MDN, handle object having an `hasOwnProperty` prop
51          var { hasOwnProperty } = Object.prototype;
52  
53          for (var i = 0; i < mapResults.length; i++) {
54              if (mapResults[i]) {
55                  var { key } = mapResults[i];
56                  var { val } = mapResults[i];
57  
58                  if (hasOwnProperty.call(result, key)) {
59                      result[key].push(val);
60                  } else {
61                      result[key] = [val];
62                  }
63              }
64          }
65  
66          return callback(err, result);
67      });
68  }
69  
70  exports.default = (0, _awaitify2.default)(groupByLimit, 4);
71  module.exports = exports['default'];