Bump to v4.0.0.

nthArg.js

@@ -0,0 +1,26 @@
+define(['./toInteger'], function(toInteger) {
+
+  /**
+   * Creates a function that returns its nth argument.
+   *
+   * @static
+   * @memberOf _
+   * @category Util
+   * @param {number} [n=0] The index of the argument to return.
+   * @returns {Function} Returns the new function.
+   * @example
+   *
+   * var func = _.nthArg(1);
+   *
+   * func('a', 'b', 'c');
+   * // => 'b'
+   */
+  function nthArg(n) {
+    n = toInteger(n);
+    return function() {
+      return arguments[n];
+    };
+  }
+
+  return nthArg;
+});