AsyncEmitter

[tshemsedinov]

ee.on('e1', async () => true);
await ee.emit('a1');

I suppose we need to hide counters when waiting for multiple event handlers to this abstraction.

[tshemsedinov]

I added tests that reveal problems and now it’s clear that we need to change data structure for wrappers. Maybe better store them mixed to functions: fn[symbolWrapper] = wrapper ? @nechaido @belochub @lundibundi

[tshemsedinov]

Implemented in a different way. Now we hold on and once in different data structures for each event separately:

AsyncEmitter {
  events:
    Map {
      'eventName' => {
        on: Set { listener<Function> },
        once: Map { listener<Function> => wrapper<Function> }
      },
  }
}

@nechaido @belochub @lundibundi

[lundibundi]

Nit: can be simplified to:

return event ? event.on.size + event.once.size : 0;

[nechaido]

I'd prefer to use Symbol('getListeners') for this, to make this property "private".

[nechaido]

Suggested change

	this.events = new Map();
	this.listeners = new Map();

[nechaido]

I'd prefer to move this one line up, because some of the listeners may create additional once listeners.

[nechaido]

?

Suggested change

	const fn = test.mustCall(async (a, b, c, d) => {
	const fn = test.mustCall(async (...args) => { test.strictSame(args, [1, 2, 3, 4]) });

[nechaido]

You should add a test, to ensure that emit args are forwarded to once listener.

[nechaido]

Suggested change

	this.once(name, resolve);
	this.once(name, (...args) => resolve(args.length <= 1 ? args[0] : args)
	);

[nechaido]

Ditto.