asmJs

Whether a function whose body starts with "use asm" is compiled ahead of time to typed code. On by default.

asm.js is the subset of JavaScript that Emscripten writes, and its types are all known before it runs, so the engine can hold an integer as an integer instead of as an object. A module the engine cannot validate runs as ordinary JavaScript either way, so this only changes speed, never answers. Turn it off to compare the two.