es6 generators, promises, abort xhr?

[redux-saga]

es6 generators, promises, abort xhr?

[wmertens]

Promise cancellation is still under discussion. Whatwg fetch (the next-gen xhr) is discussion cancellable fetching separate from promises here: whatwg/fetch#27 (interesting but very long)

[yelouafi]

@aft-luke I think the undefined issue is that you dont return a value from doFetch (return (yield req = ...))

Regarding cancellation, redux-saga cancels only the effects it creates itself (called sagas, take effects). raw promise cancellation is a no-op since this is not yet supported by the standard.

I realize cancellation is not standard yet, but my favorite promise library bluebird does support cancellation, and I have a decorated/promisified xhr library that will xhr.abort() when told.

Thanks again @yelouafi, you are right. I'm not sure I totally understand the syntax here, but return (yield someVar = ... )) makes someVar declared inside a catch block.

[aikoven]

@aft-luke redux-saga/lib/proc module exports CANCEL symbol. You can use it to add cancellation to any promise:

import {CANCEL} from 'redux-saga/lib/proc';

promise[CANCEL] = () => { /* cancellation logic */ }