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