2 ms·

Conceptually, yeah, it's not required. But in practice there are a whole lot of websites that make heavy (HEAVY) use of JS, and performance would not be accepta

Conceptually, yeah, it's not required. But in practice there are a whole lot of websites that make heavy (HEAVY) use of JS, and performance would not be acceptable for a lot of users. I'm not saying those websites are correct in doing that, but in effect browsers are expected to have JIT to maintain any userbase at all, because such websites are so numerous that it would make it seem it is an actual browser "issue" in the eyes of laypeople.

Chyzwar 6y ago
Depends. Hermes[1] JS engine from Facebook do not have JIT and provide better perf for React Native. Modern V8 have both interpreter Ignition[2] and TurboFan[3] JITed compiler. My understanding is that on most websites Ignition will be sufficient but when using omething like SPA application TurboFan will gradually speedup bytecode generated by Ignition using JIT like technology. I am not sure if JIT is required. There are even ideas to compile Typescript to WebAssembly[4]. You could create a compiler that compile strict subset of JS to more performant Webassembly and it would outperform modern JS engines. [1] https://github.com/facebook/hermes [2] https://v8.dev/docs/ignition [3] https://v8.dev/docs/turbofan [4] https://www.assemblyscript.org/