dansajin

function measureEventPerformance(event) {
  const lag = performance.now() - event.timeStamp;
  console.log(`Event took: ${lag} ms`);
}

// Usage
const submitButton = document.querySelector('button[type="submit"]');

submitButton.addEventListener('click', (event) => {
  // Event listener logic here...

dansajin

'use strict';

function Queue(){
    this.push = function(){
        for (var i = 0, len = arguments.length; i < len; i++){
            if (typeof arguments[i] !== 'function'){
                throw new TypeError('Argument must be a function.')
            }
            arguments[i]()
        }

dansajin

function overrideOnce(object, method, callback){
    // override method with original as argument
    object[method] = (function(original){
        return function(){
            // store whatever callback does
            var result = callback.apply(this, arguments);

            // restore method
            object[method] = original;

dansajin

/**
 * criticalCSS by @dansajin. based on @scottjehl's criticalcss.js
 * run this in a browser console or create a bookmarklet.
 * lists rules per css file. 
 * does not include cross origin css files and inline css.
 */
(function(){
    var sheets = document.styleSheets,
        host = window.location.host,
        maxTop = 1200,