What is Hermesjs?

Hermes JS Engine. Hermes is a JavaScript engine optimized for fast start-up of React Native apps. It features ahead-of-time static optimization and compact bytecode. … Version mismatch can result in instant crash of your apps in the worst case scenario.

Hermes on iOS made the app start ~40% faster than JSC.

Hermes is a helper created by Facebook engineers that works specially for Android. The objective of this engine is to increase the startup time of an app developed with React Native and some other memory troubles that you’ll see below.

How to Enable Hermes in React Native

After exploring other options, we built a new JavaScript engine we call Hermes. It is designed to improve app performance, focusing on our React Native apps, even on mass-market devices with limited memory, slow storage, and reduced computing power. At Chain React 2019, we announced the Hermes JavaScript engine.

How to Enable Hermes in React Native

Hermes for Android is supported from SDK 42 and above in Expo Go , development builds built with expo-dev-client and standalone apps built with EAS Build. For bare apps created before SDK 42, follow these instructions to update your project configuration.