[Bahamut]

At this point, I think Flow clearly has a minority mindshare & is looked at more skeptically all around the JS ecosystem, and maybe even the React ecosystem based on what I see talked around. TS does a much better job integrating with existing JS and is much more practical about incremental updates whereas Flow bleeds all too easily into needing to add typing to a significant amount of code in order to add a type.

That's not to say that either TypeScript or Flow are perfect - they both are constraining with typing when it comes to composing functions last I checked.

[dvlsg]

I didn't have too many problems with typescript and ramda. I occasionally have to explicitly send in types to the first function of a pipe, which is a little annoying, but for the most part it seems to just work for how I use it. What problems have you run into?

[leppr]

Have a look at the typescript declaration for Node's util.promisify (sorry on mobile can't find it right now). It's something like 10 lines long and covers only a handful of cases.

It's not something you'd want to find in the middle of your code, yet you may have to if you want to do generic/functional programming in TS.