event-target-shim

A polyfill for W3C EventTarget, plus few extensions.

See Also: https://dom.spec.whatwg.org/#interface-eventtarget

Overview

• This module provides EventTarget constructor that is possible to inherit for your custom object.
• This module provides an utility in order to define properties for attribute listeners (e.g. obj.onclick).

If window.EventTarget exists, EventTarget is inherit from window.EventTarget. In short, obj instanceof window.EventTarget === true.

declare class EventTarget {
  constructor();
  addEventListener(type: string, listener: (event: Event) => void, capture?: boolean): void;
  removeEventListener(type: string, listener: (event: Event) => void, capture?: boolean): void;
  dispatchEvent(event: Event): void;
}

// Define EventTarget type with attribute listeners.
declare function EventTarget(...types: string[]): typeof EventTarget;

Installation

npm install event-target-shim

Usage

import EventTarget from "event-target-shim";

class YourCoolType extends EventTarget {
  // ...
}

// This prototype has getters/setters of `onmessage` and `onerror`.
class YourAwesomeType extends EventTarget("message", "error") {
  // ...
}

I prefer use together with Browserify.

But we can use together with RequireJS, instead. In this case, please download a file from dist directory of repo.

define("MagicalBox", ["event-target-shim"], function (EventTarget) {
  function MagicalBox() {
    EventTarget.call(this);
  }

  MagicalBox.prototype = Object.create(EventTarget.prototype, {
    constructor: {
      value: MagicalBox,
      configurable: true,
      writable: true
    },

    // ...
  });

  return MagicalBox;
});