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					87 lines
				
				2.7 KiB
			
		
		
			
		
	
	
					87 lines
				
				2.7 KiB
			| 
											3 years ago
										 | 'use strict'; | ||
|  | 
 | ||
|  | Object.defineProperty(exports, "__esModule", { | ||
|  |     value: true | ||
|  | }); | ||
|  | exports.default = transform; | ||
|  | 
 | ||
|  | var _isArray = require('lodash/isArray'); | ||
|  | 
 | ||
|  | var _isArray2 = _interopRequireDefault(_isArray); | ||
|  | 
 | ||
|  | var _noop = require('lodash/noop'); | ||
|  | 
 | ||
|  | var _noop2 = _interopRequireDefault(_noop); | ||
|  | 
 | ||
|  | var _eachOf = require('./eachOf'); | ||
|  | 
 | ||
|  | var _eachOf2 = _interopRequireDefault(_eachOf); | ||
|  | 
 | ||
|  | var _once = require('./internal/once'); | ||
|  | 
 | ||
|  | var _once2 = _interopRequireDefault(_once); | ||
|  | 
 | ||
|  | var _wrapAsync = require('./internal/wrapAsync'); | ||
|  | 
 | ||
|  | var _wrapAsync2 = _interopRequireDefault(_wrapAsync); | ||
|  | 
 | ||
|  | function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } | ||
|  | 
 | ||
|  | /** | ||
|  |  * A relative of `reduce`.  Takes an Object or Array, and iterates over each | ||
|  |  * element in series, each step potentially mutating an `accumulator` value. | ||
|  |  * The type of the accumulator defaults to the type of collection passed in. | ||
|  |  * | ||
|  |  * @name transform | ||
|  |  * @static | ||
|  |  * @memberOf module:Collections | ||
|  |  * @method | ||
|  |  * @category Collection | ||
|  |  * @param {Array|Iterable|Object} coll - A collection to iterate over. | ||
|  |  * @param {*} [accumulator] - The initial state of the transform.  If omitted, | ||
|  |  * it will default to an empty Object or Array, depending on the type of `coll` | ||
|  |  * @param {AsyncFunction} iteratee - A function applied to each item in the | ||
|  |  * collection that potentially modifies the accumulator. | ||
|  |  * Invoked with (accumulator, item, key, callback). | ||
|  |  * @param {Function} [callback] - A callback which is called after all the | ||
|  |  * `iteratee` functions have finished. Result is the transformed accumulator. | ||
|  |  * Invoked with (err, result). | ||
|  |  * @example | ||
|  |  * | ||
|  |  * async.transform([1,2,3], function(acc, item, index, callback) { | ||
|  |  *     // pointless async:
 | ||
|  |  *     process.nextTick(function() { | ||
|  |  *         acc.push(item * 2) | ||
|  |  *         callback(null) | ||
|  |  *     }); | ||
|  |  * }, function(err, result) { | ||
|  |  *     // result is now equal to [2, 4, 6]
 | ||
|  |  * }); | ||
|  |  * | ||
|  |  * @example | ||
|  |  * | ||
|  |  * async.transform({a: 1, b: 2, c: 3}, function (obj, val, key, callback) { | ||
|  |  *     setImmediate(function () { | ||
|  |  *         obj[key] = val * 2; | ||
|  |  *         callback(); | ||
|  |  *     }) | ||
|  |  * }, function (err, result) { | ||
|  |  *     // result is equal to {a: 2, b: 4, c: 6}
 | ||
|  |  * }) | ||
|  |  */ | ||
|  | function transform(coll, accumulator, iteratee, callback) { | ||
|  |     if (arguments.length <= 3) { | ||
|  |         callback = iteratee; | ||
|  |         iteratee = accumulator; | ||
|  |         accumulator = (0, _isArray2.default)(coll) ? [] : {}; | ||
|  |     } | ||
|  |     callback = (0, _once2.default)(callback || _noop2.default); | ||
|  |     var _iteratee = (0, _wrapAsync2.default)(iteratee); | ||
|  | 
 | ||
|  |     (0, _eachOf2.default)(coll, function (v, k, cb) { | ||
|  |         _iteratee(accumulator, v, k, cb); | ||
|  |     }, function (err) { | ||
|  |         callback(err, accumulator); | ||
|  |     }); | ||
|  | } | ||
|  | module.exports = exports['default']; |