npm package (v2.0.3) cancel() kills the function

[nikparo]

In the latest version on npm (2.0.3) the cancel function does not unset the requestId, unlike the current master branch. If it is called while a raf call is queued, it effectively terminates the function permanently. Could you please publish a new version to npm?

[wuct]

Thanks for let me know! It should be released long time ago. I have just published the latest version. Let me know whether the issue still exists.

[nikparo]

Thank you. However, I ended up copying the code and extending it for our use. In particular, I added .start() and .stop() functions since I found .cancel() to be insufficient:

1. In some browsers cancelAnimationFrame() is unable to cancel callbacks pending for the current animation frame. (cancelAnimationFrame should also cancel pending callbacks whatwg/html#4359)
2. Unsubscription in other libraries (in my case redux) is not necessarily immediate and may still call the function even after their unsubscribe callback has been called.

I also added an isAnimationFrame function to check whether we are currently in an animation frame in order to call some methods immediately rather than their throttled counterparts. (Only those scheduled by raf-throttle unfortunately, I don't know whether a global check is possible.)

If you want I could open pull requests for some or all of these?

[wuct]

Oh, I did not know the cancelAnimationFrame() works differently in different browsers, thanks for the whatwg link!
I would like to keep the API minimized, but I am also curious about how do you implement .start() and .stop() 😆
Do you use a flag to check whether the registered callback should be invoked or not?

[nikparo]

Yeah, essentially it's just a flag:

const later = context => () => {
  requestId = null;
  if (!stopped) {
    callback.apply(context, lastArgs);
  }
};

const throttled = function(...args) {
  lastArgs = args;
  if (requestId === null && !stopped) {
    requestId = requestAnimationFrame(later(this));
  }
};

// ...

throttled.stop = () => {
  stopped = true;
  lastArgs = undefined;
  throttled.cancel();
};

throttled.start = () => {
  stopped = false;
};

[wuct]

Thanks for sharing 👍
I am going to close the issue since the code has been released. Feel free to reopen if the issue still existed.