findKey.js (1329B)
1 var baseFindKey = require('./_baseFindKey'), 2 baseForOwn = require('./_baseForOwn'), 3 baseIteratee = require('./_baseIteratee'); 4 5 /** 6 * This method is like `_.find` except that it returns the key of the first 7 * element `predicate` returns truthy for instead of the element itself. 8 * 9 * @static 10 * @memberOf _ 11 * @since 1.1.0 12 * @category Object 13 * @param {Object} object The object to inspect. 14 * @param {Function} [predicate=_.identity] The function invoked per iteration. 15 * @returns {string|undefined} Returns the key of the matched element, 16 * else `undefined`. 17 * @example 18 * 19 * var users = { 20 * 'barney': { 'age': 36, 'active': true }, 21 * 'fred': { 'age': 40, 'active': false }, 22 * 'pebbles': { 'age': 1, 'active': true } 23 * }; 24 * 25 * _.findKey(users, function(o) { return o.age < 40; }); 26 * // => 'barney' (iteration order is not guaranteed) 27 * 28 * // The `_.matches` iteratee shorthand. 29 * _.findKey(users, { 'age': 1, 'active': true }); 30 * // => 'pebbles' 31 * 32 * // The `_.matchesProperty` iteratee shorthand. 33 * _.findKey(users, ['active', false]); 34 * // => 'fred' 35 * 36 * // The `_.property` iteratee shorthand. 37 * _.findKey(users, 'active'); 38 * // => 'barney' 39 */ 40 function findKey(object, predicate) { 41 return baseFindKey(object, baseIteratee(predicate, 3), baseForOwn); 42 } 43 44 module.exports = findKey;