Project Description
Facebook has launched a new javascript called Hermes. This will help the React Native android applications to improve their performances. Hermes is developed to increase the startup time, decrease the Ram usage and resulting a smaller app size. Hermes is now present in all its React Native apps. Most importantly this javascript has also been used in Facebook’s Crisis Response & Oculus Companion app. Here are some features of Hermes:
Features of Hermes
Instead of making the users wait, parsing and compiling JavaScript on-device can be done at the build time.
Ahead of time compilation. Hermes is developed for fast startup.
Hermes helps the React Native apps to decrease the memory usage of the device and thus resulting a smaller app size.
As per the need bytecode can be mapped and loaded from the flash memory gradually.
In chunks an on-demand virtual address space is located to avoid the need of estimating the heap size and overhead minimizing. And the free memory can easily be returned to OS.
Hermes targets ES6, which is now not being used in the React Native applications.

Facebook has already started open sourced Hermes integration to the React Native apps; so that the developers can opt into the javascript immediately.