We have a benchmark section in the repo and it's performing pretty well, we'll definitely run it against other engines!
91 karma · joined December 20, 2018
The biggest problem I have with TypeScript is to know WHAT .ts files will be compiled into. I.e., if you're using enums or decorators, there's no plain support for them in JS so you'll end up having some kind of "polyfills", which are not so optimized.
Once you analyze your compiled JS, you can write TS knowing what you're gonna get, which is the trick to make it optimized.
My two cents :)