React 19: What you need to know?

It was 25th April 2024 when React 19 was officially released. If you love working with React, you must have already gotten into the details of it, but if you are new to React then probably there is a lot for you to check out! Happy reading 💙

Either way, let's get into the nitty-gritty of what you need to know (there is no harm in revisiting what you already know right?)

New Features in React 19

Before kicking things off, I have a quick question for you all. What challenges do you think will be addressed by React 19?

Well it is the issue of re-rendering that also impacts performance. React 19 is aimed to be a one stop solution for it. How? Let's find out.

React Compiler
React 19 introduces a new React Compiler. Before, React code only ran in the browser, but now this compiler converts React code into plain JavaScript. This makes your app start up much faster. The compiler automatically decides when to update the UI, so you don't need to manually use tools like Memo() or Callback(). This compiler is already used on Instagram and will soon be available as open-source.

Actions
Handling forms is easier in React 19 with the new Actions feature. Instead of using onSubmit events, you can now use the action attribute in your HTML form tags. This allows form submissions to run on the server, making it simpler to handle data.

Before:

<form onSubmit={handleSubmit}>
  <input name="task" />
  <button type="submit">Add Task</button>
</form>

After:

"use server";

const addTask = async (formData) => {
  const newTask = {
    task: formData.get('task'),
  };
  console.log(newTask);
};

const TaskForm = () => {
  return (
    <form action={addTask}>
      <div>
        <label>Task</label>
        <input type="text" name="task" />
      </div>
      <button type="submit">Add Task</button>
    </form>
  );
};

export default TaskForm;

Document Meta Data Section
React 19 introduces <DocumentHead>, a new feature that makes it easy to add titles and meta tags to your web pages. This improves SEO and keeps your brand consistent across different pages.

Web Components
React 19 improves the use of web components, which are like special building blocks made with HTML, CSS, and JavaScript. These improvements make it easier to integrate these components into your React projects.

Asset Loading
React 19 can load images and files in the background while users are on the current page, making transitions to new pages faster and smoother. New Resource Loading APIs like preload and preinit help control when resources should load.

Improved Hooks
React 19 also improves Hooks, giving you more control over when your code runs and updates. This results in smoother performance and easier coding.

Let's wrap up. Stay tuned as the next series will be about new hooks in React 19 and how you should use them.

Love React? ❤️ I got you.