[tampermonkey] CLS logger using web-vitals library

gistfile1.txt

// ==UserScript==
// @name         (Web-Vitals lib) Cumulative Layout Shift Measure
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Try to improve your CWV score
// @author       @jaesbit
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var script = document.createElement('script');
    script.src = 'https://unpkg.com/web-vitals@3/dist/web-vitals.iife.js';
    script.onload = function () {
      // When loading `web-vitals` using a classic script, all the public
      // methods can be found on the `webVitals` global namespace.
      webVitals.onCLS(event => console.log('[CLS-lib]', event));
      webVitals.onFID(event => console.log('[CLS-lib]', event));
      webVitals.onLCP(event => console.log('[CLS-lib]', event));
    };
    document.head.appendChild(script);
})();