lodash/ary.js

define(['./_createWrap'], function(createWrap) {

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

  /** Used to compose bitmasks for function metadata. */
  var WRAP_ARY_FLAG = 128;

  /**
   * Creates a function that invokes `func`, with up to `n` arguments,
   * ignoring any additional arguments.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Function
   * @param {Function} func The function to cap arguments for.
   * @param {number} [n=func.length] The arity cap.
   * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
   * @returns {Function} Returns the new capped function.
   * @example
   *
   * _.map(['6', '8', '10'], _.ary(parseInt, 1));
   * // => [6, 8, 10]
   */
  function ary(func, n, guard) {
    n = guard ? undefined : n;
    n = (func && n == null) ? func.length : n;
    return createWrap(func, WRAP_ARY_FLAG, undefined, undefined, undefined, undefined, n);
  }

  return ary;
});