undefined | Better HN

0 pointsmasklinn12y ago0 comments

> Promises are declining, and honestly doesn't really solve the problem in most cases. A couple of years from now, you won't see promises on the server. You should see tjholowaychuk/visionmedia's co[1]; that's how JS is going to look like in future.

I'm impressed that you apparently completely failed to realise co is an abstractive layer over promises, something it states upfront:

> Generator based flow-control goodness for nodejs (and soon the browser), using thunks or promises

What you yield from your generator is not magical pixie dusts, it's promises.

0 comments

4 comments · 2 top-level

sync12y ago· 2 in thread

Actually, it's not promises. It's generators.

co thunkifies promises: https://github.com/visionmedia/co/blob/master/index.js#L209-...

masklinnOP12y ago

> Actually, it's not promises. It's generators.

The generator is the driver, but the driver on its own its useless if it's got nothing to drive.

And what it has to drive is promises (or thunks since most existing node code is thunks-based I guess it makes sense to support that. taskjs uses promises more or less exclusively for the same purpose, Python 3.4's asyncio uses behaving much like JS promises, etc...)

jeswin12y ago

Seems you have misunderstood how it works. https://github.com/visionmedia/co/blob/master/index.js

Typically in apps using 'co', functions will return generators, not promises. Promises were probably added because of all the existing code out there.

Here is a file from my ongoing project, should explain how generators are being used. See getPosts() or addPost() https://github.com/jeswin/fora/blob/master/server/src/models...

[Edit: Just read your earlier (Gr.GP) comment. Might want to avoid the unnecessary snark, especially when there's a chance you might be wrong.]

1 more reply

ulisesrmzroche12y ago

You can also use plain functions, objects, array, and even other generators too. Least, that's what the framework tells me when I fuck up my tests. It's not just all promises under the hood.

j / k navigate · click thread line to collapse