Typescript seriously needs to start getting its act together. The roadmap shows they're making some headway on these new es6 features, but it feels like they're trying to both accept it for es6 output mode, and for es3/es5 output mode. This means further delays, during which period we can't use them at all.
And because typescript != javascript, we can't use any other tools, either. TS is duplicating the 6to5 efforts, with little to show for it.
If you use TS, right now you're stuck with es5. It's starting to itch.
I wish they'd prioritize the es6 features in es6 output mode and let me worry about converting that to es5.
Internally TS is a two pass compilation. First type check, then transpile to ES5.
The type check step should be available to run on its own. IMO they should not even worry about transpiling, just be a type checking engine.
The API for TS, last I used it, was extremely limited. It has always been viewed as a black box compiler by the authors- they need to expose more flexibility.
This comes from being on a current version of V8... Node.js has always been a little behind, and since 0.10 has become very stagnant. Part of the reason for the shift to io.js
"Show unstable platforms" + "Sort by number of features" is quite interesting: IE preview wins among browsers. Firefox is close second, and both are ahead of and V8 and even Google's Traceur transpiler.
Number of features isn't a terribly useful comparison, however, since it assumes all features are equal. It's like taking the arithmetic mean of very different benchmarks as a benchmark score.
Writing tests for 'let' support, for instance, is harder than just testing that all the Array.prototype methods are now on TypedArrays, so those methods are worth twice that of let support, even though let is considerably more complicated to implement and game changing in its consequences.
And that's why we give different weight to different features. Smallest ones (Math methods, octal & binary literals, etc.) have a weight of 0.25. Medium ones (Map, Set, rest parameters, etc.) have a weight of 0.5. Finally, landmark features (arrow functions, classes, generators) have a weight of 1.
The final % score is calculated according to all this.
It would be interesting to see what a combination of Browser + library would support, or to work out which library would increase support over the most browsers.
Maybe it would be a good idea to add a note in the meantime. I was quite confused when the module stuff was gone. I assumed it was moved to ES7, but it didn't show up there either. I finally learned the truth after googling a bit and finding that issue. Would have been nice if the page would have told me that right away.
Is this the only noteworthy ES6 feature which isn't tested?
And because typescript != javascript, we can't use any other tools, either. TS is duplicating the 6to5 efforts, with little to show for it.
If you use TS, right now you're stuck with es5. It's starting to itch.
I wish they'd prioritize the es6 features in es6 output mode and let me worry about converting that to es5.