findKey.js 1.3 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445
  1. var baseFindKey = require('./_baseFindKey'),
  2. baseForOwn = require('./_baseForOwn'),
  3. baseIteratee = require('./_baseIteratee');
  4. /**
  5. * This method is like `_.find` except that it returns the key of the first
  6. * element `predicate` returns truthy for instead of the element itself.
  7. *
  8. * @static
  9. * @memberOf _
  10. * @since 1.1.0
  11. * @category Object
  12. * @param {Object} object The object to search.
  13. * @param {Array|Function|Object|string} [predicate=_.identity]
  14. * 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. module.exports = findKey;