ES6 Generator support

[wizzard0]

This can be broken down to 3 areas:

1. basic (parser) support, even if we lose typechecking locally
2. Typechecking support
3. Transpiling like facebook/regenerator or Traceur, for targeting ES3/ES5.

Any timelines on this?

[DanielRosenwasser]

We have basic parser support (#1268). As our roadmap specifies, 1.5 is the target for emit, though I'm not sure if that includes the ES3/ES5 polyfill.

Since I don't see an official issue tracking it, I think this might be a good candidate!

[JsonFreeman]

Please take a look at #2873 and let me know if this addresses your needs.

[buzinas]

I've just seen that the TypeScript 2.0 milestone was added to support transpiling generators to ES5: do you have any estimate when it will be released?

[omidkrad]

@buzinas I don't know when to expect it but until then the workaround is to get TypeScript code with async/await transpiled to ES6 and then in a second build step use Babel to transpile that to ES5.

[buzinas]

@omidkrad Yeah, I know that, did this for one project, but for the others, I'm trying to keep things dry, so, I'm using only TypeScript as transpiler.

For bigger projects, the build time of two transformations doesn't compensate for us. Also, the sourcemaps don't work well when transpiling two times, unfortunately (they work, but poorly sometimes).

At the moment, we're sticking with promises, and it's good enough for 90% of the cases.

[DanielRosenwasser]

I think we'll have a beta ready to use towards late May/early July, though no promises on dates.

[piotrwitek]

@omidkrad For me using Babel just for transpiling async/await to ES5 was a a little bit of overkill, so for that workaround in my projects I'm currently using https://github.com/facebook/regenerator, works fine, but I cannot wait to finally have it possible by only using TS

[omidkrad]

@piotrwitek Nice tip! Do you run generator on tsc's ES5 output?