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node_modules/when/keys.js 1.97 KB
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  /** @license MIT License (c) copyright 2011-2013 original author or authors */
  
  /**
   * Licensed under the MIT License at:
   * http://www.opensource.org/licenses/mit-license.php
   *
   * @author Brian Cavalier
   * @author John Hann
   */
  (function(define) { 'use strict';
  define(function(require) {
  
  	var when = require('./when');
  	var Promise = when.Promise;
  	var toPromise = when.resolve;
  
  	return {
  		all: when.lift(all),
  		map: map
  	};
  
  	/**
  	 * Resolve all the key-value pairs in the supplied object or promise
  	 * for an object.
  	 * @param {Promise|object} object or promise for object whose key-value pairs
  	 *  will be resolved
  	 * @returns {Promise} promise for an object with the fully resolved key-value pairs
  	 */
  	function all(object) {
  		var p = Promise._defer();
  		var resolver = Promise._handler(p);
  
  		var results = {};
  		var keys = Object.keys(object);
  		var pending = keys.length;
  
  		for(var i=0, k; i<keys.length; ++i) {
  			k = keys[i];
  			Promise._handler(object[k]).fold(settleKey, k, results, resolver);
  		}
  
  		if(pending === 0) {
  			resolver.resolve(results);
  		}
  
  		return p;
  
  		function settleKey(k, x, resolver) {
  			/*jshint validthis:true*/
  			this[k] = x;
  			if(--pending === 0) {
  				resolver.resolve(results);
  			}
  		}
  	}
  
  	/**
  	 * Map values in the supplied object's keys
  	 * @param {Promise|object} object or promise for object whose key-value pairs
  	 *  will be reduced
  	 * @param {function(value:*, key:String):*} f mapping function which may
  	 *  return either a promise or a value
  	 * @returns {Promise} promise for an object with the mapped and fully
  	 *  resolved key-value pairs
  	 */
  	function map(object, f) {
  		return toPromise(object).then(function(object) {
  			return all(Object.keys(object).reduce(function(o, k) {
  				o[k] = toPromise(object[k]).fold(mapWithKey, k);
  				return o;
  			}, {}));
  		});
  
  		function mapWithKey(k, x) {
  			return f(x, k);
  		}
  	}
  
  });
  })(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); });