This is far from the first attempt to do bring multithreading/parallelism into JS. A (failed) example: https://en.wikipedia.org/wiki/River_Trail_(JavaScript_en

This is far from the first attempt to do bring multithreading/parallelism into JS. A (failed) example: https://en.wikipedia.org/wiki/River_Trail_(JavaScript_engine) https://en.wikipedia.org/wiki/River_Trail_(JavaScript_engine... Another attempt (although a different approach) is here : https://github.com/tc39/ecmascript_sharedmem https://github.com/tc39/ecmascript_sharedmem Hopefully, Microsoft will learn from the errors of others. Interestingly, napa is build on V8, not on MS own javascript engine.