ReactDOM.createRoot() vs ReactDOM.render()

'ReactDOM.render()' and 'ReactDOM.createRoot()' are both methods provided by React for rendering React elements into the DOM, but they serve slightly different purposes and have different usage patterns.

ReactDOM.render():

• This method is the traditional way of rendering React elements into the DOM.
• It takes two arguments: first, the React element or component to render and second, the DOM element where it should be rendered.
• It is typically used in applications where the entire UI is rendered at once, such as in single-page applications.

Example:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

ReactDOM.render(
   <App />, document.getElementById('root')
);

ReactDOM.createRoot():

• This method is part of the new concurrent mode feature introduced in React 18 and is designed for more advanced use cases.
• It returns a 'Root' object that allows you to asynchronously render and update React elements in a more fine-grained manner.
• It is recommended for applications that need to incrementally render parts of the UI or handle updates in a more asynchronous and prioritized manner, such as large-scale applications or applications with complex UI interactions.

Example:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<App />);

Summary:

'ReactDOM.render()' is suitable for most applications and provides a straightforward way to render React elements into the DOM, while 'ReactDOM.createRoot()' is more advanced and provides greater control over rendering and updating for applications with complex requirements or those adopting concurrent mode features.