But that'd still be transpiled code, right? After getting rid of flow it will be exactly same minus the type annotations. Same cannot be said about typescript considering various language features and syntactic sugar TS offers. Will it run? Yes. Will it feel that it was written by me? That depends.
> Same cannot be said about typescript considering various language features and syntactic sugar TS offers
I think you're vastly misinterpreting what TS is.
It's not anything like CoffeeScript. It's JS plus types and a few other features like Interfaces or advanced ECMAScript features when targetting older versions of the standard.
If you strip away types by exporting to your ECMAScript target of choice, you'll get real JavaScript with the same style as it was written in TypeScript.
It's exactly the same thing you'd get with Flow in that sense. The only additional code you'd get would be for polyfills, but a) those are minimal and b) those will only appear if you export to an older ECMAScript version than the one you wrote it in.
there are a few minor things like enums and decorators that will need to be compiled because they're not standard and are not just types either (well, const enums are i think?, but the rest are not?).
Your equivalence with transpiling coffeescript is false. TS doesn't really have "syntactic sugars". Just about everything in it(less the types of course) is pretty far along in the ES adoption process. There are a couple exceptions like decorators that are called out in a very visible manner.
If you target ES6 your code may look identical. Even much of the ES5 down leveling produced code that looks like a person wrote it.
I converted a 10k line coffeescript project(with async/await !) to JS and then TypeScript. The similarities are so far apart they might as well be in different dimensions. But, if you don't want to take a rando posters word for it, it's pretty easy to make a little sample project and see if the output is to your liking.