keyBy.js (1194B)
1 var baseAssignValue = require('./_baseAssignValue'), 2 createAggregator = require('./_createAggregator'); 3 4 /** 5 * Creates an object composed of keys generated from the results of running 6 * each element of `collection` thru `iteratee`. The corresponding value of 7 * each key is the last element responsible for generating the key. The 8 * iteratee is invoked with one argument: (value). 9 * 10 * @static 11 * @memberOf _ 12 * @since 4.0.0 13 * @category Collection 14 * @param {Array|Object} collection The collection to iterate over. 15 * @param {Function} [iteratee=_.identity] The iteratee to transform keys. 16 * @returns {Object} Returns the composed aggregate object. 17 * @example 18 * 19 * var array = [ 20 * { 'dir': 'left', 'code': 97 }, 21 * { 'dir': 'right', 'code': 100 } 22 * ]; 23 * 24 * _.keyBy(array, function(o) { 25 * return String.fromCharCode(o.code); 26 * }); 27 * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } } 28 * 29 * _.keyBy(array, 'dir'); 30 * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } } 31 */ 32 var keyBy = createAggregator(function(result, value, key) { 33 baseAssignValue(result, key, value); 34 }); 35 36 module.exports = keyBy;