1  'use strict';
 2  
 3  Object.defineProperty(exports, "__esModule", {
 4      value: true
 5  });
 6  
 7  var _once = require('./internal/once');
 8  
 9  var _once2 = _interopRequireDefault(_once);
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   * Runs the `tasks` array of functions in parallel, without waiting until the
23   * previous function has completed. Once any of the `tasks` complete or pass an
24   * error to its callback, the main `callback` is immediately called. It's
25   * equivalent to `Promise.race()`.
26   *
27   * @name race
28   * @static
29   * @memberOf module:ControlFlow
30   * @method
31   * @category Control Flow
32   * @param {Array} tasks - An array containing [async functions]{@link AsyncFunction}
33   * to run. Each function can complete with an optional `result` value.
34   * @param {Function} callback - A callback to run once any of the functions have
35   * completed. This function gets an error or result from the first function that
36   * completed. Invoked with (err, result).
37   * @returns undefined
38   * @example
39   *
40   * async.race([
41   *     function(callback) {
42   *         setTimeout(function() {
43   *             callback(null, 'one');
44   *         }, 200);
45   *     },
46   *     function(callback) {
47   *         setTimeout(function() {
48   *             callback(null, 'two');
49   *         }, 100);
50   *     }
51   * ],
52   * // main callback
53   * function(err, result) {
54   *     // the result will be equal to 'two' as it finishes earlier
55   * });
56   */
57  function race(tasks, callback) {
58      callback = (0, _once2.default)(callback);
59      if (!Array.isArray(tasks)) return callback(new TypeError('First argument to race must be an array of functions'));
60      if (!tasks.length) return callback();
61      for (var i = 0, l = tasks.length; i < l; i++) {
62          (0, _wrapAsync2.default)(tasks[i])(callback);
63      }
64  }
65  
66  exports.default = (0, _awaitify2.default)(race, 2);
67  module.exports = exports['default'];