The React team has introduced their own compiler, which aims to minimize the effort developers need to put in and significantly boost their productivity. Currently, the React compiler is an experimental feature and is not yet production-ready. But that won't stop us from exploring the exciting possibilities of the new *React Compiler*. Let's get started!

What Sets the Compiler Apart

When writing code, you no longer need to worry about memoizing your code to prevent side effects that impact performance or cause unnecessary rendering on the screen.

If you're familiar with React, you've likely encountered useCallback, useMemo, and memo. These APIs inform React that a component doesn't need to re-compute if its inputs remain the same. For a deeper understanding of these APIs, refer to the official documentation here.

While these APIs are excellent for grasping memoization and its workings, it's common to forget to use them or use them incorrectly. Even the most experienced developers can make mistakes that result in significant performance drawbacks.

The compiler leverages its understanding of JavaScript and the Rules of React to automatically memoize your components and hooks. If you inadvertently break the rules of React, the compiler will skip that file and continue compiling the remaining code.

Assumptions Made by the Compiler

1. Your code is valid and semantically correct JavaScript.
2. You adhere to the Rules of React.
3. You ensure that nullable/optional values and properties are defined before accessing them.

Utilizing the React Compiler

To discover how to integrate the React compiler into your existing codebase, refer to the steps outlined in the documentation.

React Compiler requires React 19 RC. Make sure to upgrade to React 19 before using the React compiler.

You can experiment with the compiler in any project that has React as a dependency. For instance, your Next.js project can seamlessly integrate with the React compiler.

Remember to install the ESLint plugin for a clearer understanding of issues you may encounter while strictly adhering to the rules of React.

Integrating with Your Codebase

Due to JavaScript's flexible nature, the compiler may not detect all possible violations and may proceed with false negatives. (The compiler may unintentionally compile files that violate the rules of React, which is not the desired behavior.)

You can start by introducing the compiler to a small portion of your extensive codebase. Adopt it in a specific directory first:

const ReactCompilerConfig = {
  sources: (filename) => {
    return filename.indexOf('src/path/to/dir') !== -1;
  },
};

For a new codebase, you can enable the compiler for your entire codebase, which is the default behavior.

TL;DR

• With the React compiler, memoization is taken care of for you, eliminating the need to worry about it.
• The compiler is available for experimental use but is not yet ready for production deployments.
• To ensure the React compiler can work its magic, you must follow the rules of React.
• The compiler can be used with any project that has React as a dependency.