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

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/