How to put three.js scene into react.js app:

1. Create react app: create-react-app my-app
2. Add three.js: yarn add three
3. Copy and paste spinning cube example from three.js front page, and expose a function to interact with react.js:

export function mount( container ) {
    if( container ) {
        container.insertBefore( renderer.domElement, container.firstChild );
        resize();
    } else {
        renderer.domElement.remove();
    }
}

In react component, pass this function to useCallback:

import { mount } from './3d';

export default function Cube() {
    const containerRef = useCallback(mount, []);
    return <div className="Cube-container" ref={containerRef}></div>
}

4. Add some tests if you feel like.