[xiaodai]

how can you compile it if javascript is a valid subset of typescript? confused.

[panzi]

Either it is only accepting a subset of TypeScript, or it is still interpreting the parts that don't have enough types. Given other comments here it sounds like the later.

[lpribis]

No idea about this project, but it is very possible to compile a dynamically typed language, without large VM/runtime. See Common Lisp, Julia

[queenkjuul]

Both, basically. Default is the subset, but you can enable an interpreter

[CarpeNecopinus]

What it can actually compile is a subset of well-behaved typescript. For anything else it bails out and asks you to ship a JS engine (albeit, not NodeJS) again.