HORIZON PROJECT

'use strict';

Object.defineProperty(exports, "__esModule", {

    value: true

});

exports.default = race;

var _isArray = require('lodash/isArray');

var _isArray2 = _interopRequireDefault(_isArray);

var _noop = require('lodash/noop');

var _noop2 = _interopRequireDefault(_noop);

var _once = require('./internal/once');

var _once2 = _interopRequireDefault(_once);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**

 * Runs the `tasks` array of functions in parallel, without waiting until the

 * previous function has completed. Once any of the `tasks` complete or pass an

 * error to its callback, the main `callback` is immediately called. It's

 * equivalent to `Promise.race()`.

 *

 * @name race

 * @static

 * @memberOf module:ControlFlow

 * @method

 * @category Control Flow

 * @param {Array} tasks - An array containing functions to run. Each function

 * is passed a `callback(err, result)` which it must call on completion with an

 * error `err` (which can be `null`) and an optional `result` value.

 * @param {Function} callback - A callback to run once any of the functions have

 * completed. This function gets an error or result from the first function that

 * completed. Invoked with (err, result).

 * @returns undefined

 * @example

 *

 * async.race([

 *     function(callback) {

 *         setTimeout(function() {

 *             callback(null, 'one');

 *         }, 200);

 *     },

 *     function(callback) {

 *         setTimeout(function() {

 *             callback(null, 'two');

 *         }, 100);

 *     }

 * ],

 * // main callback

 * function(err, result) {

 *     // the result will be equal to 'two' as it finishes earlier

 * });

 */

function race(tasks, callback) {

    callback = (0, _once2.default)(callback || _noop2.default);

    if (!(0, _isArray2.default)(tasks)) return callback(new TypeError('First argument to race must be an array of functions'));

    if (!tasks.length) return callback();

    for (var i = 0, l = tasks.length; i < l; i++) {

        tasks[i](callback);

    }

}

module.exports = exports['default'];