sortBy.js 2.0 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859
  1. var baseFlatten = require('./_baseFlatten'),
  2. baseOrderBy = require('./_baseOrderBy'),
  3. isArray = require('./isArray'),
  4. isFlattenableIteratee = require('./_isFlattenableIteratee'),
  5. isIterateeCall = require('./_isIterateeCall'),
  6. rest = require('./rest');
  7. /**
  8. * Creates an array of elements, sorted in ascending order by the results of
  9. * running each element in a collection thru each iteratee. This method
  10. * performs a stable sort, that is, it preserves the original sort order of
  11. * equal elements. The iteratees are invoked with one argument: (value).
  12. *
  13. * @static
  14. * @memberOf _
  15. * @since 0.1.0
  16. * @category Collection
  17. * @param {Array|Object} collection The collection to iterate over.
  18. * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
  19. * [iteratees=[_.identity]] The iteratees to sort by.
  20. * @returns {Array} Returns the new sorted array.
  21. * @example
  22. *
  23. * var users = [
  24. * { 'user': 'fred', 'age': 48 },
  25. * { 'user': 'barney', 'age': 36 },
  26. * { 'user': 'fred', 'age': 40 },
  27. * { 'user': 'barney', 'age': 34 }
  28. * ];
  29. *
  30. * _.sortBy(users, function(o) { return o.user; });
  31. * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
  32. *
  33. * _.sortBy(users, ['user', 'age']);
  34. * // => objects for [['barney', 34], ['barney', 36], ['fred', 40], ['fred', 48]]
  35. *
  36. * _.sortBy(users, 'user', function(o) {
  37. * return Math.floor(o.age / 10);
  38. * });
  39. * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
  40. */
  41. var sortBy = rest(function(collection, iteratees) {
  42. if (collection == null) {
  43. return [];
  44. }
  45. var length = iteratees.length;
  46. if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
  47. iteratees = [];
  48. } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
  49. iteratees = [iteratees[0]];
  50. }
  51. iteratees = (iteratees.length == 1 && isArray(iteratees[0]))
  52. ? iteratees[0]
  53. : baseFlatten(iteratees, 1, isFlattenableIteratee);
  54. return baseOrderBy(collection, iteratees, []);
  55. });
  56. module.exports = sortBy;