My understanding is, direct port is more expensive besides toy projects of course, looking at Bun and also listening to people who've done a few language conversions, they extract something first.

If not an intermediate representation, my first question would be: how to split the work. You cannot just prompt full rewrite of 60K LoC, you cannot do it module by module — modules do translate 1:1, like in my case golang packages did not matched Rust crates. Bun did file by file.

With hierarchical state machines in the middle, I did it almost in one shot.