lodash/differenceBy.js

define(['./_baseDifference', './_baseFlatten', './_baseIteratee', './_baseRest', './isArrayLikeObject', './last'], function(baseDifference, baseFlatten, baseIteratee, baseRest, isArrayLikeObject, last) {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /**
   * This method is like `_.difference` except that it accepts `iteratee` which
   * is invoked for each element of `array` and `values` to generate the criterion
   * by which they're compared. The order and references of result values are
   * determined by the first array. The iteratee is invoked with one argument:
   * (value).
   *
   * **Note:** Unlike `_.pullAllBy`, this method returns a new array.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Array
   * @param {Array} array The array to inspect.
   * @param {...Array} [values] The values to exclude.
   * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
   * @returns {Array} Returns the new array of filtered values.
   * @example
   *
   * _.differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);
   * // => [1.2]
   *
   * // The `_.property` iteratee shorthand.
   * _.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
   * // => [{ 'x': 2 }]
   */
  var differenceBy = baseRest(function(array, values) {
    var iteratee = last(values);
    if (isArrayLikeObject(iteratee)) {
      iteratee = undefined;
    }
    return isArrayLikeObject(array)
      ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), baseIteratee(iteratee, 2))
      : [];
  });

  return differenceBy;
});