https://github.com/firebase/blaze_compiler
Typescript has been a joy to develop in. The codebase is a mix of typescript and plain JS for some of the parsing.
There are a few interesting architectures patterns like a work around for no subclassing of Error by wrapping an error with a backwards chained decorator
https://github.com/firebase/blaze_compiler/blob/master/src/e...
(thanks to mindplay for that idea here https://typescript.codeplex.com/discussions/465345)
That product is still in it's infancy so gradually being refactored towards full modularisation, so its still a work in progress.
FYI: I use pycharm with the node.js plugin, and typescript compiles in the background without intervention, and I can step debug the program, and the line at the top off all the files transparent changes the stack traces back into TS.
I also just finished building this app [1] for homeless youth in Minnesota using TypeScript and Angular.
[0]: https://github.com/JudahGabriel/ravendb/tree/master/Raven.St...
[1]: http://ysnmn.org