[Felz]

Funny, I was using the source-map library under Nashorn. The performance was poor enough that I had to switch to embedding V8; I'm not sure whether that was a consequence of Nashorn itself being too slow, or the Javascript optimizations intended for V8/Firefox just completely missing their mark.

Not that the WASM version of the library would've helped, since Nashorn doesn't do WASM at all. But maybe the performance would've been decent if it had.