Yes, but it can’t easily interop with the host language. Elisp saves the stack, which you can’t do in JS. That means you can’t cross JS -> elisp boundaries with your longjmp without some pretty awful hacks.

You cannot longjmp across 'native' stackframes (which mightor might not be a big limitation), but otherwise interop should be fine. The native interpreter stack is always around to be used to run native function calls.