lodash/collection/forEach.js

define(['../internal/arrayEach', '../internal/baseEach', '../internal/bindCallback', '../lang/isArray'], function(arrayEach, baseEach, bindCallback, isArray) {

  /**
   * Iterates over elements of `collection` invoking `iteratee` for each element.
   * The `iteratee` is bound to `thisArg` and invoked with three arguments;
   * (value, index|key, collection). Iterator functions may exit iteration early
   * by explicitly returning `false`.
   *
   * **Note:** As with other "Collections" methods, objects with a `length` property
   * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
   * may be used for object iteration.
   *
   * @static
   * @memberOf _
   * @alias each
   * @category Collection
   * @param {Array|Object|string} collection The collection to iterate over.
   * @param {Function} [iteratee=_.identity] The function invoked per iteration.
   * @param {*} [thisArg] The `this` binding of `iteratee`.
   * @returns {Array|Object|string} Returns `collection`.
   * @example
   *
   * _([1, 2]).forEach(function(n) {
   *   console.log(n);
   * }).value();
   * // => logs each value from left to right and returns the array
   *
   * _.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
   *   console.log(n, key);
   * });
   * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
   */
  function forEach(collection, iteratee, thisArg) {
    return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
      ? arrayEach(collection, iteratee)
      : baseEach(collection, bindCallback(iteratee, thisArg, 3));
  }

  return forEach;
});