I actually started LazyPromise without knowing much about Effect (https://www.effect.website/), coming from the world of RxJS and Solid-style signals (my post from last year: https://news.ycombinator.com/item?id=46321852). But Effect is a lazy promise too, and showed how useful generator syntax, type-safe errors and dependency injection can be. So there you go: a version of promise with...
About the two error channels: what I tried to do is to make it really easy to not use typed errors when you don't need them. In that case your promise is typed as `LazyPromise<Value, never>`.
Signals is a reactive primitive that has been initially introduced in SolidJS framework and have then made their way to other frameworks like Angular.
https://github.com/lazy-promise/lazy-promise
A Promise-like primitive which is lazy/cancelable, has typed errors, and emits synchronously instead of on the microtask queue. In a way LazyPromise is what you get if you take an Observable and make it impossible to misuse it for what the Signals were built to do.
UPD: sorry, I just realized you were talking about Reason, never mind.