How Hermes improves React Native performanceįor JavaScript-based mobile applications, user experience benefits from attention to a few primary metrics: We are excited to work with the open source community and have developers start using Hermes today. We have open-sourced the Hermes engine, as well as integration with Hermes for React Native. 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.Īt Chain React 2019, we announced the Hermes JavaScript engine. After exploring other options, we built a new JavaScript engine we call Hermes. With this data in hand, we knew we had to optimize JavaScript performance in the more constrained environments of a mobile phone compared with a desktop or laptop. As we analyzed performance data, we noticed that the JavaScript engine itself was a significant factor in startup performance and download size. To increase the performance of Facebook’s apps, we have teams that continuously improve our JavaScript code and platforms. These issues are generated from various spots, but the people using these apps expect them to run smoothly, regardless of the device they are on. Larger apps using JavaScript frameworks often experience performance issues as developers add features and complexity. Mobile applications are growing larger and more complex.

Facebook for android 51 download