shrink too long title attribute for UserScript

title-attr-shrinker.user.js

// ==UserScript==
// @name        title attr shrinker
// @namespace   http://noromanba.flavors.me
// @description shrink too long title attribute for UserScript
// @include     http://example.com/DIY
// @grant       none
// @noframes
// @run-at      document-end
// @version     2017.2.22.1
// @homepage    https://gist.github.com/noromanba/f71a9da49f2e44b5c9fc0645f15c05f3
// @downloadURL https://gist.github.com/noromanba/f71a9da49f2e44b5c9fc0645f15c05f3/raw/title-attr-shrinker.user.js
// @license     MIT License https://nrm.mit-license.org/2017
// @author      noromanba   http://noromanba.flavors.me
// @icon        https://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Internet-group-chat.svg/128px-Internet-group-chat.svg.png
// ==/UserScript==

// Icon (PD by By Jakub Steiner/Tango! project)
// https://commons.wikimedia.org/wiki/File%3AInternet-group-chat.svg

// Devel
// https://gist.github.com/noromanba/f71a9da49f2e44b5c9fc0645f15c05f3

// Bookmarklet
// http://let.hatelabo.jp/noromanba/let/hJmeyeG6sc9H


// via
// http://let.hatelabo.jp/a-kuma3/let/hJmeyNv-p802
//  http://q.hatena.ne.jp/1487159409
//  http://q.hatena.ne.jp/images/question/1487159/1487159409.jpg

// hatenanews on http://www.hatena.ne.jp/ has been fixed

(() => {
  'use strict';

  Array.from(document.body.querySelectorAll([
    // write <a> selector(s) as you like
  ]), (link, idx) => {
    if (!link.href) return;

    const shrink = () => {
      const xhr = new XMLHttpRequest();

      xhr.open('GET', link.href);
      xhr.timeout = 3000;
      xhr.responseType = 'document';

      xhr.addEventListener('load', () => {
        if (xhr.readyState !== xhr.DONE || xhr.status !== 200) return;

        const ctx = xhr.response.document;

        const title = (ctx.querySelector([
          'head title'
        ]) || {}).textContent || '';
        const descr = (ctx.querySelector([
          'head meta[property="og:description"][content]',
          'head meta[name="twitter:description"][content]',
        ]) || {}).content || '';

        const shrinked = title + '\n' + descr;
        link.title = shrinked;
      });

      xhr.send();
    };

    const INTERVAL = 500;
    setTimeout(shrink, INTERVAL * idx);
  });

})();