If you’re a developer, you’ve probably heard of JavaScript. But have you heard of Hermes?
It’s a relatively new JavaScript engine that was created by Facebook. In this article, we will take a closer look at what Hermes is and why it could be beneficial for your projects.
What Is a JavaScript Engine?
First, let’s define what a JavaScript engine is. A JavaScript engine is responsible for interpreting and executing JavaScript code.
It takes your code and turns it into something the computer can understand and execute. Common examples of JavaScript engines include V8 (used by Google Chrome) and SpiderMonkey (used by Mozilla Firefox).
What Is Hermes?
Hermes is an open-source JavaScript engine that was created by Facebook specifically for use with React Native applications. The primary goal of creating Hermes was to improve the performance of React Native applications on mobile devices.
One way that Hermes improves performance is through its memory management capabilities. It uses a technique called garbage collection, which helps to free up memory that is no longer being used by the application. This can help to prevent memory-related crashes and improve overall performance.
Another way that Hermes improves performance is through its bytecode format. When you write code in a high-level language like JavaScript, the code needs to be translated into machine code before it can be executed by the computer.
With traditional JavaScript engines, this translation process happens every time the code runs, which can be slow. However, with Hermes, the translation happens only once when the application is built, which makes subsequent runs much faster.
Why Should You Use Hermes?
If you’re building a React Native application for mobile devices, then using Hermes could provide several benefits:
Better Performance: As mentioned earlier, Hermes can help improve the performance of your application through its memory management capabilities and bytecode format.
Smaller App Size: Because bytecode takes up less space than the original JavaScript code, using Hermes can help reduce the size of your application. This can be especially beneficial for users with limited storage space on their devices.
Improved User Experience: Faster load times and smoother animations can lead to a better user experience overall.
How to Use Hermes
If you’re interested in using Hermes for your React Native application, you’ll need to make sure that you’re using version 0.60 or higher of React Native. After that, all you need to do is enable Hermes in your project’s configuration file.
Here’s how you can do it:
- Open your project’s
metro.config.jsfile. - Add the following code:
“`
module.exports = {
transformer: {
getTransformOptions: async () => ({
transform: {
experimentalImportSupport: false,
inlineRequires: false,
hermesParser: true,
},
}),
},
};
“`
That’s it! Once you’ve enabled Hermes, your application will use the new JavaScript engine.
Conclusion
In summary, Hermes is a new open-source JavaScript engine created by Facebook specifically for use with React Native applications. It offers several benefits such as improved performance and smaller app size. If you’re building a React Native application for mobile devices, consider giving Hermes a try to see if it can help improve your application’s performance and user experience.