I installed the module via npm, required it as said in the docs (Browserify 16.2.2 handles the bundling).

const EventTarget = require('event-target').default;

but I get an error:

Safari 11.1 (doesn't have EventTarget constructor)
TypeError: undefined is not a constructor (evaluating 'new EventTarget')

FF 61 (has support, works perfect w/o polyfill)
TypeError: EventTarget is not a constructor

Including the script tag from the CDN works though.

Seen in Safari 11.1
Works fine in Chrome 66.0.3359.139

Using browser event target implementation:

let eventTarget;
eventTarget = document.createElement('div');
eventTarget.addEventListener('foo', () => console.log(1), {once: true});
eventTarget.addEventListener('foo', () => console.log(2), {once: true});
eventTarget.dispatchEvent(new CustomEvent('foo'))

1
2

Using polyfill:

eventTarget = new EventTarget; 
eventTarget.addEventListener('foo', () => console.log(1), {once: true});
eventTarget.addEventListener('foo', () => console.log(2), {once: true});
eventTarget.dispatchEvent(new CustomEvent('foo'))

1

Using polyfill without once option:

eventTarget = new EventTarget; 
eventTarget.addEventListener('foo', () => console.log(1));
eventTarget.addEventListener('foo', () => console.log(2));
eventTarget.dispatchEvent(new CustomEvent('foo'))

1
2

I use the following with webpack to import the polyfill:

import EventTarget from 'event-target/esm/index.js';

Currently when requiring in CJS, (according to documentation) one has to do:

const EventTarget = require('event-target').default;

It'll be way more natural if it's:

const EventTarget = require('event-target');

Is this fixable?

If I see correctly support for ES3 engines is not ensured.

(so Every. JavaScript. Engine. statement is not true ;-))

While it's not common to write for ES3 engines these days. It still can be the case in some scenarios, and EventTarget is core interface to many functionalities.

As now both FF and Chrome provide EventTarget as normal extensible class, wouldn't it be good to return it by default in those engines?

See step 2.7 of https://dom.spec.whatwg.org/#concept-event-listener-inner-invoke

Unfortunately, I don't know off the top of my head what the best way to report the exception would be.

• console.error
• `window.dispatchEvent('error', new Error(...))
• something else?

Following evaluate to false when setting window.EventTarget using the polyfill

import EventTarget from 'event-target/esm/index.js'

console.log(EventTarget instanceof window.EventTarget);

import EventTarget from 'event-target/esm/index.js'

console.log(document.createElement('div') instanceof EventTarget);

Not sure if it is possible to get either of these to evaluate to true..?