Hi @devanshj ,

Thank you very much for your great module! I run into the same issue as you before today. (see: wechaty/redux#4)

After performed my google-fu, I found your issue ReactiveX/rxjs#4891, and here, where I believe it will be my final destination. ;^)

I'm using the TypedEmitter which is really nice to type my emitter classes, when I use fromEmitter() with the typedEmitter, I found that if we have more than one event, unfortunately we will get an unknown typing with the returned Observable, which I believe it is a bug.

Minimum Reproducible Code

import { EventEmitter }   from 'events'
import TypedEventEmitter  from 'typed-emitter'

import { fromEmitter } from 'rxjs-from-emitter'

interface Events {
  foo: (n: number) => void
  bar: (s: string) => void
}
const TypedEmitter = EventEmitter as new () => TypedEventEmitter<Events>

const emitter = new TypedEmitter()

const $ = fromEmitter(emitter).event('foo')
// const $: Observable<unknown>

If we remove bar in the Events interface, then the $ will be able to be inference right: const $: Observable<number>

I tried to dive into your code to fix it, however, the Typing code is more than I expected.

Would really appreciate it if we can get our fromEmitter works with typedEmitter, thank you for your time for my issue, and looking forward to seeing your reply.