React 19 compiler

To understand the duties of a react compiler, first lets know about React memoization

What is Memoization?

React memoization is nothing but a technique to optimizing the performance of the React components. 

We know that we are nesting components into other components. sometimes if one component state is updated other components will also re-render unnecessary. Unnecessary re-renders may cause performance issues in our React applications. When a component re-renders, React needs to re-calculate the state or other logics, this can be a time-consuming process. If a component re-renders continuously, the application may slow down.

To solve this problem we are using useMemo() and useCallback() hooks and also memo() higher order function. This is called Manual memoization. 

Now lets talks about what is Automatic memoization? How React 19 Compiler will solve the memoization problems

What is a React Compiler?

React Dev finished the development of the compiler to make it more reliable and capable of our react applications. This compiler allows us to analyze and memoize more complex patterns such as local mutations(mutation is nothing but, process of changing the value of a variable or object within a specific scope, without affecting its value outside of that scope. ) and memoization hooks.

Automatic memoization

React compiler that automatically generates the equivalent of useMemo and useCallback calls to minimize the cost of re-rendering. we can also call this as an automatic reactivity compiler

The objective of React Forget for React developers is to maintain optimal reactivity levels in React applications, ensuring that components re-render only when necessary due to meaningful changes in state values. This is achieved by automatically employing memoization techniques. However, we advocate for framing this concept within the context of reactivity, believing it provides a clearer understanding of React and Forget's purpose. Essentially, React currently triggers re-renders based on changes in object identity. With Forget, re-renders occur when the semantic value changes, but without incurring the runtime overhead of deep comparisons.

Already started using react compiler

React Compiler is no longer a research project: the compiler now powers instagram.com in production, and Meta started working to ship the compiler across additional surfaces at Meta and to prepare the first open source release.

React 19 Version

There is still more to do to prepare for release. In React 19, React Dev is also adding long-requested improvements which require breaking changes like support for Web Components. Our focus now is to land these changes, prepare for release, finalize docs for new features, and publish announcements for what’s included.