map.js 1.6 KB

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  1. var arrayMap = require('./_arrayMap'),
  2. baseIteratee = require('./_baseIteratee'),
  3. baseMap = require('./_baseMap'),
  4. isArray = require('./isArray');
  5. /**
  6. * Creates an array of values by running each element in `collection` thru
  7. * `iteratee`. The iteratee is invoked with three arguments:
  8. * (value, index|key, collection).
  9. *
  10. * Many lodash methods are guarded to work as iteratees for methods like
  11. * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
  12. *
  13. * The guarded methods are:
  14. * `ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
  15. * `fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
  16. * `sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
  17. * `template`, `trim`, `trimEnd`, `trimStart`, and `words`
  18. *
  19. * @static
  20. * @memberOf _
  21. * @since 0.1.0
  22. * @category Collection
  23. * @param {Array|Object} collection The collection to iterate over.
  24. * @param {Function} [iteratee=_.identity] The function invoked per iteration.
  25. * @returns {Array} Returns the new mapped array.
  26. * @example
  27. *
  28. * function square(n) {
  29. * return n * n;
  30. * }
  31. *
  32. * _.map([4, 8], square);
  33. * // => [16, 64]
  34. *
  35. * _.map({ 'a': 4, 'b': 8 }, square);
  36. * // => [16, 64] (iteration order is not guaranteed)
  37. *
  38. * var users = [
  39. * { 'user': 'barney' },
  40. * { 'user': 'fred' }
  41. * ];
  42. *
  43. * // The `_.property` iteratee shorthand.
  44. * _.map(users, 'user');
  45. * // => ['barney', 'fred']
  46. */
  47. function map(collection, iteratee) {
  48. var func = isArray(collection) ? arrayMap : baseMap;
  49. return func(collection, baseIteratee(iteratee, 3));
  50. }
  51. module.exports = map;