Promise.done() doesn't return a promise, docs say it should.

[oderby]

Perhaps I'm misunderstanding something here, but the API reference indicates that Promise.done() should return a promise (https://github.com/petkaantonov/bluebird/blob/master/API.md#donefunction-fulfilledhandler--function-rejectedhandler---function-progresshandler----promise)

But I've noticed that doesn't appear to be the case, and indeed looking at the source, the done method doesn't return anything (https://github.com/petkaantonov/bluebird/blob/master/src/promise.js#L140)

I'm not sure what is the proper behavior, but I think done() should return a promise.

My use case is something akin to the following: I have a server handling a client request. So I do the following

var promise = Promise.try(processRequest).cancellable().then(sendResponse).catch(handleError).done()
response.on('close', function() {promise.cancel();})

The problem is whenever the client disconnects before I respond, I can't cancel the promise because the promise var is undefined (because done() doesn't return anything).

[petkaantonov]

It's not supposed to return anything so the docs are wrong.

[benjamingr]

Personally I find unhandled rejection detection quite good and avoid 'done' altogether, that said:

I think it should return the same promise it gets as input - this is usually the assumed behavior since it's what other APIs do.

On 22 במרץ 2014, at 20:31, Antonov [email protected] wrote:

It's not supposed to return anything so the docs are wrong.

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[benjamingr]

On second thought returning nothing is also acceptable IMO. I used .done when using jQuery to return a promise and handle it's resolution but that's just as easy as creating a temp reference to it.

[petkaantonov]

@benjamingr No other library's done returns the promise, it's always undefined.

[domenic]

Returning undefined enforces good behavior, i.e. using done() as a chain terminator instead of a brancher.

[oderby]

Okay, makes sense that done() should return nothing.

[petkaantonov]

Fixed in e18fc46