EventDispatcher converted to es6

[treblereel]

Related issue: #19986

[donmccurdy]

Note that this change could have downstream effects on classes that extend Object3D:

three.js/src/core/Object3D.js

Lines 115 to 119 in 670b1e9

	Object3D.prototype = Object.assign( Object.create( EventDispatcher.prototype ), {
	constructor: Object3D,
	isObject3D: true,

It may not — I don't see any calls to super.* methods — but this would need to be tested and confirmed.

[mrdoob]

Yeah, I suspect this change will break everything.

@treblereel Have you tested this?

[treblereel]

@mrdoob yeap, i my case all good. i also checked demos and got no issues

[DefinitelyMaybe]

Hey, quick question on this one: Could we simply extend EventTarget and add the hasEventListener function?

class EventDispatcher extends EventTarget {
  hasEventListener( type, listener ) {
  // ...  
  }
}

[Mugen87]

Does not work in node.js.

[DefinitelyMaybe]

Actually it was added into node.js v15.0.0
Happy to not accept this into the fray now but later it may be nice.

[treblereel]

Actually it was added into node.js v15.0.0
Happy to not accept this into the fray now but later it may be nice.

ok, good to know, closing this PR

[Mugen87]

Could we simply extend EventTarget and add the hasEventListener function?

Just want to add that a benchmark showed that using EventTarget is noticeably slower compared to the current implementation.

[DefinitelyMaybe]

oh shoot. that's a big difference. Thank you for pointing that one out @Mugen87. Let's stick with what we got