[typescript] Should I use a promise to represent an event that can occur at most once, may never occur but can never fail? If not, what else should I use? Callbacks?

Well actually the event occurs several times but it doesn't really make sense to listen to multiple of them so I only have a function to catch the next one.

I'm using rxjs observables and unsubscribing upon invocation. It's a hack, a horrible one I must say, judging by how difficult it is to unsub, but it works. I wonder what others do tho.

Edit: I'm not a js/ts dev 😁

Lacking background knowledge, how do you want to represent an event as a Promise ? There is basically no difference to use a promise or callbacks. It’s just syntactic sugar IMO.

@dder The difference is in semantics. Promises can reject anytime for any reason. If a callback has no "error" argument you know there's nothing to handle. At the same time, promises can only be resolved once, for a callback that isn't a given. However, one might assume that a promise will resolve or reject at some point, whereas in my case that can't be known.
Additionally, with promises I have much less control over references so it's harder to let the user cancel the request and ensure that the handler gets GCd.

Oh, and Promises can be passed to Promise.all([...]) as opposed to callbacks.