Reddit.com to i.reddit.com UserScript

// ==UserScript==
// @name        URL Conversion | Reddit > i.reddit
// @namespace   pandasun
// @description reddit to i.reddit
// @include     *reddit*
// @version     1
// @grant       none
// @run-at document-start
// ==/UserScript==

var url = window.location.toString();
if (url.indexOf('https://www.reddit.com') !== - 1) {
  window.location = url.replace(/www.reddit.com/, 'i.reddit.com');
}