engine262 VS hermes

engine262

Indeed. ECMA-262 has been implemented using JavaScript https://github.com/engine262/engine262.

Node.js is not the only JavaScript runtime. JavaScript runtimes have been written using JavaScript alone, see engine262. There is also Deno, QuickJS, txiki.js, Bun, none of which use COmmonJS by default, SpiderMonkey, et al.

for an interpreted language like JS, this project is really nice https://github.com/engine262/engine262. More or less 2 parts: parser and evaluator

That is a bit complex, so here's a list of JS engines: if you pick one written *in* JS, that would probably be most useful -- engine262 for example

then you might be impressed by https://github.com/engine262/engine262 as well

Engine 262

It's outside of what you asked for, but here's a JavaScript engine in JavaScript. Might make for some interesting bedtime reading!

Interesting to see a JS implementation written in JS:

https://github.com/engine262/engine262/

(The readme explains what the point of it is.)

Hermes is a big one as well: low startup latency, low memory

https://hermesengine.dev/

Hermes

InstagramBundle.js.hbc.spk.xz is likely a compressed version of Hermes bytecode (js.hbc)"

In React Native's case, it uses an engine called Hermes:

📜 I made JSON.parse() 2x faster: Radek proposes to improve the performance of Hermes by using very fast C++ libs based on SIMD instructions. Interesting to read even if you don't use React-Native. Ongoing discussions on the Hermes PR.

Thanks! There's a preliminary PR with a discussion here: https://github.com/facebook/hermes/pull/933 (and broader context here: https://github.com/facebook/hermes/issues/811 ). But we'll see if there's any interest on Hermes' side to merging it. They definitely want to improve the parser, but it's unclear to me if they want to take on the simdjson/simdutf dependencies.

For me it’s a JS engine for React Natve - https://hermesengine.dev/

💉 Building and injecting a JS bundle a basic concept: If the native code wasn’t changed, simply create JS bundle and inject it into the precompiled application. (You must take an extra step to convert a js file to bytecode if you use the Hermes js engine.)