Upgrade To React 19

Upgrade React 18 to 19

Bumps react, react-dom, and the React type packages from 18 to 19. React 19 removes several long-deprecated APIs; the change every project hits is the root API (ReactDOM.render -> createRoot). Read more in the React 19 upgrade guide.

The paired AI instructions migration walks an agent through the full set of changes. The common ones are shown below.

Examples

Before

import ReactDOM from 'react-dom';

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

After

import { createRoot } from 'react-dom/client';

createRoot(document.getElementById('root')!).render(<App />);

defaultProps on a function component becomes a default parameter:

Before

function Badge({ color }) {}
Badge.defaultProps = { color: 'gray' };

After

function Badge({ color = 'gray' }) {}