shivam1283

Callback

function loadScript(src) {
  // creates a <script> tag and append it to the page
  // this causes the script with given src to start loading and run when complete
  let script = document.createElement('script');
  script.src = src;
  document.head.append(script);
}

Rich-Harris

( function ( global ) {

	'use strict';

	var Promise, PENDING = {}, FULFILLED = {}, REJECTED = {};

	if ( typeof global.Promise === 'function' ) {
		Promise = global.Promise;
	} else {
		Promise = function ( callback ) {