SO Hangouts Authuser Redirect

so_hangouts_auth.user.js

// ==UserScript==
// @name         SO Hangouts Authuser Redirect
// @namespace    http://m0sa.net/
// @version      1.1
// @description  authuser=1
// @author       m0sa
// @include      https://plus.google.com/hangouts/_/stackoverflow.com/*
// @include      https://hangouts.google.com/hangouts/_/stackoverflow.com/*
// @grant        none
// ==/UserScript==

var authuser = 1;
var initial  = window.location.href;
var clean    = initial.split('#')[0].replace(/[\?&]authuser=\d+/, '');
var updated  = clean + (clean.indexOf('?') >=0 ? '&' : '?') + 'authuser=' + authuser + window.location.hash;
if (initial != updated) 
{ 
    window.location.href = updated;
}