what is the difference between react17 and react 18?

 

React 18 introduced several improvements over React 17, focusing on performance, concurrent rendering, and developer experience. Here are the key differences:

1. Concurrent Rendering

• React 17: Used a synchronous rendering model, meaning updates were processed one at a time.
• React 18: Introduced concurrent rendering, allowing React to pause and resume rendering tasks, improving responsiveness.

2. Automatic Batching

• React 17: Only batched state updates inside event handlers.
• React 18: Automatically batches updates across asynchronous functions, reducing unnecessary re-renders.

3. New Root API

• React 17: Used ReactDOM.render().
• React 18: Introduced createRoot(), improving rendering performance and enabling concurrent features.

4. Suspense for Data Fetching

• React 17: Suspense was limited to code splitting.
• React 18: Expanded Suspense to support data fetching, making it easier to handle asynchronous operations.

5. Improved Server-Side Rendering (SSR)

• React 17: SSR was synchronous.
• React 18: Introduced streaming SSR, allowing components to be progressively sent to the client, improving load times.

6. New APIs

• React 18: Added startTransition(), allowing developers to prioritize updates for smoother UI interactions.