Create Emitter of a healthy mind

[tshemsedinov]

type Listener = (data: unknown) => void;
type EventName = string | symbol;

export class Emitter {
  emit(eventName: EventName, data: unknown): Promise<void>;
  on(eventName: EventName, listener: Listener): void;
  once(eventName: EventName, listener: Listener): void;
  off(eventName: EventName, listener?: Listener): void;
  toPromise(eventName: EventName): Promise<unknown>;
  toAsyncIterable(eventName: EventName): AsyncIterable<unknown>;
  clear(eventName?: EventName): void;
  listeners(eventName?: EventName): Listener[];
  listenerCount(eventName?: EventName): number;
  eventNames(): EventName[];
}

Iteration example:

const ee = new Emitter();

for await (const user of ee.toAsyncIterable('user')) {
  console.log({ user });
}

1. ee.toAsyncIterable('user') will return new AsyncIterable('user')
2. for/await will call asyncIterable[Symbol.asyncIterator] will return AsyncIterator
3. asyncIterator.next will return AsyncIteratorStep { done, value }

[GoodLuckMister]

Hi ! Could I complete this issue ?

[tshemsedinov]

Yes, this is just a draft, it might be useful, but it needs some work, maybe the contracts are not convenient, maybe the implementation can be optimized, more tests, use cases, docs, etc.

[tshemsedinov]

@GoodLuckMister You can do that

[tshemsedinov]

Example 1:

const ee = new Emitter();
for await (const chunk of ee.toIterator('chunk')) {
  console.log({ chunk });
}

Example 2:

const ee = new Emitter();
const readable = Readable.from(ee);
readable.pipe(target);

[tshemsedinov]

@GoodLuckMister @serrhiy I'd prefer you will work together. Please rename our EventEmitter to Emitter to emplasis its alternative implementation and incompatibility while stay close related abstraction.

[tshemsedinov]

@GoodLuckMister @serrhiy Please note than we move from multiple arguments in event (...args: unknown[]) to single one (data: unknown)

[serrhiy]

@GoodLuckMister email me (listed in my profile) so we can coordinate actions