fwiw, TypeScript -> Babel is doable, if painful. I have it set up in my repo here: https://github.com/thomasboyt/manygolf https://github.com/thomasboyt/manygolf

fwiw, TypeScript -> Babel is doable, if painful. I have it set up in my repo here: https://github.com/thomasboyt/manygolf https://github.com/thomasboyt/manygolf I agree that Flow currently the superior type system (and, unlike TypeScript, not a complete nightmare to set up if you're wanting to use Babel/Webpack instead of manually running file builds through your editor like it's 2002), but TypeScript has significantly more momentum behind it making it a much more practical solution for basically anyone who doesn't currently work at Facebook. There are also several exciting new features coming to the type system that brings it closer to parity with Flow: Non-nullable types: https://github.com/Microsoft/TypeScript/pull/7140 https://github.com/Microsoft/TypeScript/pull/7140 Control flow type analysis: https://github.com/Microsoft/TypeScript/pull/8010 https://github.com/Microsoft/TypeScript/pull/8010 I wish TypeScript tried to better-integrate with the greater JavaScript ecosystem and stop acting as a language of its own. Thankfully, the "es6" target gets it pretty close (I think it still compiles some es7 features, meaning you can't have Babel handle everything yet), and the non-standard module syntax seems to be a thing of the past. I hope the gap can be bridged between the TypeScript and Babel communities, so that TypeScript can one day be shipped as a Babel transform, same as Flow.