React 19 Features: Complete Guide & Migration Tips

React 19 brings significant improvements to developer experience and performance. At Softechinfra, our web development team has adopted these features in production for projects like TalkDrill and AppliedView.

Major New Features

1. Actions - Simplified Server Interactions

Actions revolutionize how we handle form submissions and server mutations:

function UpdateProfile() {
  async function updateName(formData: FormData) {
    'use server'
    await db.users.update(formData.get('name'))
  }
  return (
    <form action={updateName}>
      <input name="name" />
      <button type="submit">Update</button>
    </form>
  )
}

2. useFormStatus Hook

Access form state from any child component:

import { useFormStatus } from 'react-dom'
function SubmitButton() {
  const { pending } = useFormStatus()
  return (
    <button disabled={pending}>
      {pending ? 'Submitting...' : 'Submit'}
    </button>
  )
}

3. useOptimistic for Instant UI

Implement optimistic UI updates elegantly:

function Messages({ messages }) {
  const [optimisticMessages, addOptimistic] = useOptimistic(
    messages,
    (state, newMessage) => [...state, newMessage]
  )
  async function sendMessage(formData) {
    addOptimistic({ text: formData.get('text'), sending: true })
    await submitMessage(formData)
  }
}

4. use() Hook - Promises in Components

Use promises and context directly without useEffect:

function Comments({ commentsPromise }) {
  const comments = use(commentsPromise)
  return comments.map(c => <Comment key={c.id} {...c} />)
}

5. Document Metadata in Components

Handle SEO metadata directly in components:

function BlogPost({ post }) {
  return (
    <article>
      <title>{post.title}</title>
      <meta name="description" content={post.excerpt} />
      <h1>{post.title}</h1>
    </article>
  )
}

Breaking Changes

Migration Strategy

Performance Improvements

React 19 delivers significant performance gains:

• Improved hydration reduces Time-to-Interactive
• Better SSR streaming for faster First Contentful Paint
• Reduced bundle size with removed legacy APIs
• Faster rendering through compiler optimizations

For related performance techniques, read our Next.js Performance Optimization Guide.

Adoption for New vs Existing Projects

Learn more about modern development in our Full-Stack TypeScript Guide and see how our QA team ensures quality in React migrations.