Support wrapping an existing promise about p-cancelable HOT 8 CLOSED

@bisubus no particular problem, totally unrelated to inheritance. It's just I needed cancellation for certain patterns related, but not strictly coupled to React (like handling race conditions etc).

I've made my own lib for that: https://github.com/slorber/awesome-imperative-promise

from p-cancelable.

@sindresorhus I finally was able to find back this React blog post explaining what I want to do: https://reactjs.org/blog/2015/12/16/ismounted-antipattern.html

Also, note that this lib does not work with React Native, only in prod mode. I got errors, as far as I remember it was due to Object.setPrototypeOf(PCancelable.prototype, Promise.prototype);

I'm going to use the solution in the blog post instead, just wanted to let you know

from p-cancelable.

Promises are eager, so it has already started by the time you pass it to PCancelable.fromPromise. That's why it must be wrapped in a function.

Why are you even using this module if you don't intend to handle the cancelation? :)

from p-cancelable.

from p-cancelable.

I'm using it mostly to disable then callbacks

What do you mean by that? Example?

from p-cancelable.

from p-cancelable.

I'm using it mostly to disable then callbacks, not to tear down resources.

Btw, there are also cases we could not only disable then callbacks but also tear down resources.

For example, ajax, we could call xhr.abort() before the server responds when canceling a Promise.

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@sindresorhus Can we reopen the issue? It's legit IMO. If you need to wrap existing promise, you really do.

My primary case for cancelable promises are promise-based APIs like HTTP requests. PCancelable alone would feel like promise constructor antipattern to me here:

const fromPromise = (promise, onCancel) => (
	new PCancelable((resolve, reject, addCancelHandler) => {
		addCancelHandler(onCancel);
		promise.then(resolve, reject);
	});
);

fromPromise(
    fetch(url, { signal: controller.signal }),
    () => controller.abort()
);

Notice that executor param name in documentation is misleading; on implies that it's a handler, while it's a function that registers a handler. Could be addCancelHandler or so.

@slorber Can you elaborate what was the problem with React in your case? I believe I had issues with Promise inheritance before.

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