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

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 5 hours ago \| parent \| next [-]
		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 8 hours ago \| parent \| prev [-]
		Both, basically. Default is the subset, but you can enable an interpreter

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CarpeNecopinus 8 hours ago | parent | prev [-]

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.