@exadel/esl/polyfills/es5-target-shim.ts

Exadel Smart Library (ESL) is the lightweight custom elements library that provide a set of super-flexible components

/** Shim for ES5 style inheritance support of classes in modern browsers */
export function shimES5Constructor(Class: new (...args: any[]) => any): void {
  if (window.Reflect === undefined || typeof Class !== 'function') return;
  if (String(Class).indexOf('[native code]') === -1) return;
  const constructor = function (...args: any[]): any {
    return Reflect.construct(Class, args, this.constructor);
  };
  Object.defineProperty(constructor, 'name', {value: Class.name});
  Object.defineProperty(window, Class.name, {value: constructor});
  const Element = (window as any)[Class.name];
  Element.prototype = Class.prototype;
  Element.prototype.constructor = Element;
  Object.setPrototypeOf(Element, Class);
}

shimES5Constructor(Event);
shimES5Constructor(HTMLElement);