map.js 2.4 KB
define(['../internal/arrayMap', '../internal/baseCallback', '../internal/baseMap', '../lang/isArray'], function(arrayMap, baseCallback, baseMap, isArray) {

  /**
   * Creates an array of values by running each element in `collection` through
   * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
   * arguments: (value, index|key, collection).
   *
   * If a property name is provided for `iteratee` the created `_.property`
   * style callback returns the property value of the given element.
   *
   * If a value is also provided for `thisArg` the created `_.matchesProperty`
   * style callback returns `true` for elements that have a matching property
   * value, else `false`.
   *
   * If an object is provided for `iteratee` the created `_.matches` style
   * callback returns `true` for elements that have the properties of the given
   * object, else `false`.
   *
   * Many lodash methods are guarded to work as iteratees for methods like
   * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
   *
   * The guarded methods are:
   * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
   * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
   * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
   * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
   * `sum`, `uniq`, and `words`
   *
   * @static
   * @memberOf _
   * @alias collect
   * @category Collection
   * @param {Array|Object|string} collection The collection to iterate over.
   * @param {Function|Object|string} [iteratee=_.identity] The function invoked
   *  per iteration.
   * @param {*} [thisArg] The `this` binding of `iteratee`.
   * @returns {Array} Returns the new mapped array.
   * @example
   *
   * function timesThree(n) {
   *   return n * 3;
   * }
   *
   * _.map([1, 2], timesThree);
   * // => [3, 6]
   *
   * _.map({ 'a': 1, 'b': 2 }, timesThree);
   * // => [3, 6] (iteration order is not guaranteed)
   *
   * var users = [
   *   { 'user': 'barney' },
   *   { 'user': 'fred' }
   * ];
   *
   * // using the `_.property` callback shorthand
   * _.map(users, 'user');
   * // => ['barney', 'fred']
   */
  function map(collection, iteratee, thisArg) {
    var func = isArray(collection) ? arrayMap : baseMap;
    iteratee = baseCallback(iteratee, thisArg, 3);
    return func(collection, iteratee);
  }

  return map;
});