canonicalize URL for UserScript/Bookmarklet

canonicalizer.user.js

// ==UserScript==
// @name        canonicalizer
// @namespace   http://noromanba.flavors.me
// @description canonicalize URL for UserScript/Bookmarklet
// @include     http://example.com/DIY
// @grant       none
// @noframes
// @run-at      document-body
// @version     2016.10.31.1
// @homepage    https://gist.github.com/noromanba/3705f2e9ebb8538328b2f3f9a6f1a9b3
// @downloadURL https://gist.github.com/noromanba/3705f2e9ebb8538328b2f3f9a6f1a9b3/raw/canonicalizer.user.js
// @contributor noromanba   https://gist.github.com/noromanba/d730ccf3ae5e6916cd60 (Fork of)
// @license     MIT License https://nrm.mit-license.org/2016
// @author      noromanba   http://noromanba.flavors.me
// @icon        https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/BSicon_uxSPLa.svg/128px-BSicon_uxSPLa.svg.png
// ==/UserScript==


// Icon (PD by YLSS)
// https://commons.wikimedia.org/wiki/File%3ABSicon_uxSPLa.svg

// Devel
// https://gist.github.com/noromanba/3705f2e9ebb8538328b2f3f9a6f1a9b3


//*/
(() => {
    const canonical = () => {
        'use strict';

        // avoid contextual `head.querySelector`, nullable; e.g. PDFium
        // og:url c.f.
        // http://ogp.me
        return (document.querySelector('head meta[property="og:url"][content]') || {}).content ||
            (document.querySelector('head link[rel="canonical"][href]') || {}).href ||
            location.href;
    };

    //location.href = canonical();
    // TODO replaceState keep title in browser history
    //history.replaceState(null, null, canonical());
    history.pushState(null, null, canonical());
})();
// Bookmarklet
/*/
javascript:(()=>{const canonical=()=>{return(document.querySelector('head meta[property="og:url"][content]')||{}).content||(document.querySelector('head link[rel="canonical"][href]')||{}).href||location.href;};history.pushState(null,null,canonical());})();
//*/