In recent blog posts of February 2024 from React Labs, we learned that the React team is working on some new features which will simplify web development and improve overall performance.

What’s New:

• React Compiler

• Actions

• Directives

• Document Metadata

• Asset Loading

Let’s dive into what React 19 has in much detail.

React Compiler

The introduction of the React compiler will significantly help us improve the application’s performance. We usually encounter some issues where React can sometimes re-render too much on state changes. To avoid this, we are used to using useMemo, useCallback, and memo to perform manual memoization. But it’s a compromise, as it requires custom logic and extra code.

Since React is widely used for its simple UI function of state with JavaScript values and idiomatic nature, the React team has introduced the React compiler which helps us overcome unnecessary component re-renders. It will increase the application's overall performance.

Actions

The Actions can help us minimize the use of API, as it provides server actions which can be directly invoked from <Form/>’s action attributes. This can be used synchronously or asynchronously.

It can be defined with the ‘use server’ directive. To have access to the form submission lifecycle, React provides hooks like useFormStatus and useFormState to have access to form state and form action.

Along with this, React has also introduced useOptimistic hook for managing optimistic state updates. Actions aim to set the same philosophy for React to provide the same programming model across all environments.

New Features from React Canary will be shipped to React latest.

Directives

The “use client” and “use server” directives will split points between the front-end and server-side environments. “use client” will instruct the builder to create a script tag, while "use server” instructs to generate a POST endpoint. This can help developers to write both client and server-side code in the same file.

Document Metadata

This can provide built-in support for rendering <title>, <meta>, and metadata tags from anywhere in your component tree. This provides the same built-in feature as React Helmet used to.

Asset Loading

The React team has also integrated Suspense loading of resources such as stylesheets, fonts, and scripts. Also, the new update has new resource loading APIs like preload and preinit to provide greater control over the resource lifecycle.

Conclusion

React 19 is here to make building applications a lot easier and better in many ways. With new features like React Compiler, Actions, and Directives, the code will be much simpler and easier to maintain.

It will blur the line between frontend and backend; server actions and Directives will open newer approaches to maintain full-stack applications.

I highly appreciate these new features as they help frontend developers explore newer horizons.