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That's correct, all JS engines except for Safari's detect "use asm".

More specifically, Firefox and Edge detect "use asm" and run an asm.js type-checker, while Chrome detects "use asm" and runs TurboFan.

Nor does Chrome, but I think Chrome takes the `"use asm";` as a hint to use certain optimisations.

Chrome should enable turbo fan with the "use asm"; set. Though the only confirmation of this is saying it's tested in beta. https://code.google.com/p/v8/issues/detail?id=2599#c77

It's in release Chrome currently.

Or, potentially, does an equally good job optimizing the code with or without the asm.js hint.