Co throws when no callback provided

[kof]

Co throws an error when no done callback provided.

1. There are mostly examples without any callback
2. Throwing error means it will land as uncaughtException

First of all its a documentation issue. But I think throwing errors is not a solution at all. Instead done callback should be non optional parameter.

[kof]

Oh I see why you did an optional callback .... because you expect that everything within co is wrapped with try/catch ... hmmm

[kof]

I am not sure what to do to avoid other people trap on this like me. First of all better documentation of the done callback. And probably all examples should use try/catch within co?

[tj]

probably just better docs, no point doing try/catch within co since co itself acts like a big try/catch, just propagates by default but I think that's better than the error getting lost in limbo. maybe when promises are everywhere we just return a promise and do whatever they do (what does a promise do if it has no handler? just wait until there is one?)

[jonathanong]

if i have a question related to promises, i always ping @domenic!

[kof]

Regarding to promises, we have them already in 0.11 harmony version where generators actually work. So we can actually use the global Promise object.

[jonathanong]

there are apparently some bugs with it. we could always "look for a promise library" if one isn't available and except users to include their own

[kof]

which bugs? can you point me?

[kof]

I mean as far as then and catch works as expected, it should be ok.

[iliakan]

I've read somewhere in docs that "co must be used in real life only with a callback". That saved some of my time when I learned it, but wasn't obvious from the examples.

Maybe it's worth to use a callback in examples too.

[tj]

I'm -1 on promises until it's the v8 impl and it's decent

[kof]

the question is what's wrong with the current Promise object in v8.

[tj]

I haven't used them, I've heard they're super slow but that's alright I guess as long as they're not broken, not a real bottleneck anyway

[iliakan]

My 5cents: I've heard current V8 promises are not up2date with the spec.

People suggest to use bluebird.

[domenic]

V8 promises are up to date.

The version of V8 that ships with Node 0.11 has a minor bug where it handles invalid arguments incorrectly.

The biggest problem is nodejs/node-v0.x-archive#7714 which is a Node bug.

[kof]

@domenic looks also like a minor issue to me, no?

[domenic]

@kof not really; using promises + setTimeout + nextTick can be pretty common (e.g. test runners testing a promise API). Once all three of those ingredients are present in a program, things break pretty massively.