repack VS hermes

Re.Pack is a bundler replacement for React Native's Metro bundler. It is a series of plugins for the popular Webpack bundler that enables some key features of "plain" React designed for code-splitting and lazy loading. WARNING: Using Re.Pack, although pretty straightforward, is a bigger change than the above. So experiment with above recommendations first.

We use our own Re.Pack, which is built around webpack and leverage Module Federation to support this kind of architecture optimally, allowing for collaborative and/or independent development and deployment. Repack doesn’t currently support Expo for development, but it should be possible to have it work in standalone mode for any mini-app. We could consider building this with you.

Maintaining a React Native app built in 2017. Biggest pain right now is using the Metro bundler. Since migrating our codebase from a Yarn v1 workspace to a Rush (pnpm-based) monorepo, our packages use symlinks which the Metro bundler doesn't support. I've had to go through solutions such as Microsoft's @rnx-kit/metro-resolver-symlinks but still end up with issues. Will look next in to trying Callstack's repack for building our apps instead of Metro, even though I'm very hesitant in switching build tools.

re:pack, a Webpack bundler for RN.

Re.pack is basically a toolkit that allows you to use Webpack and its Code-Splitting functionality and use them on React Native.

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.)