[Schampu]

AssemblyScript initially targeted TS->WASM compilation, by only supporting a strict subset of the TS language. But at some point they dropped that idea and defined their own TS-like language. I don't know the reason for this, but my guess is that TS is too dynamic to just directly compile it to WASM?

[pjmlp]

Microsoft has done exactly the same on their MakeCode IoT compiler, using TypeScript and Python.

"MakeCode Languages: Blocks, Static TypeScript and Static Python"

https://makecode.com/language

It is very hard to generate good AOT code when dealing with dynamic languages, of any kind.