polyfill ES2018 standard library stuff for ES Modules supporting browsers (Edge 16+, Firefox 60+, Chrome 61+, Safari 10.1+)

esmodules-polyfill.js

if (!('trimStart' in String.prototype)) String.prototype.trimStart = String.prototype.trimLeft;
if (!('trimEnd' in String.prototype)) String.prototype.trimEnd = String.prototype.trimRight;

if (!('forEach' in NodeList.prototype)) NodeList.prototype.forEach = [].forEach;

if (!('description' in Symbol.prototype)) {
  Object.defineProperty(Symbol.prototype, 'description', {
    get() { return /\((.+)\)/.exec(this)[1] }
  });
}

if (!('finally' in Promise.prototype)) {
  Promise.prototype.finally = function(t){if("function"!=typeof t)return this.then(t,t);const e=this.constructor||Promise;return this.then(o=>e.resolve(t()).then(()=>o),o=>e.resolve(t()).then(()=>{throw o}))});
}