End streams never seem to end

An end stream never seems to end. This can lead to memory leaks if you need listeners on the end-stream. I have the following code:

appRouter.use('/test/', function(req, resp) {
    let resp$ = flyd.stream();
    flyd.on(v => { resp.write(v) }, resp$);
    flyd.on(v => { resp.end() }, resp$.end);
    doAction(resp$);
});

Now doAction can emit as much output it wants to resp$ which is written as a response. At the end it simply emits via resp$.end(true) to end the response. But it seams that the end-stream isn’t closed after it so its handler stays alive which leaks the whole closure (including the resp object for example).

Or is there maybe a way to listen for a stream ending without using ‘on’ on the end-stream?

[c-dante]

@paldepind, I was actually thinking of how to nicely represent end streams (I’ve been tinkering with a stream representation inspired by flyd – trying to figure out what the concerns should be), and my answer to the end stream problem is that you can have it point to itself. Which is almost what’s happening now with it being dependent on the trueFn.

Really, then, Stream is a recursive type.

So,

var s = stream();
s.end === s.end.end;

Which makes perfect sense – if s.end() === true then we expect s.end.end() === true and so forth, and none of the “is ended” logic fails.

[StreetStrider]

I’ve noticed that type signature for end is different from regular streams (Flow). I believe this is because of end streams have no end. In my typed code sometimes I go away from flyd$Stream and use weaker function definition as a stream abstraction.

Implementing @c-dante’s idea will lead to filling that gap in typings: end stream will be fully fledged stream, because of having of all attributes of regular stream.