Three.js simple rotating cube tutorial

HTML

<script src="https://threejs.org/build/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js"></script>
<script src="https://threejs.org/examples/js/libs/dat.gui.min.js"></script>

CSS

body {
  margin: 0;
  overflow: hidden;
}

JavaScript

let raycaster, intersected;
const scene = new THREE.Scene();

const mouse = new THREE.Vector2();
const camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 300);
camera.position.set(2, 5, 3);

	raycaster = new THREE.Raycaster();

  let geometry = new THREE.BoxGeometry();
  geometry = geometry.toNonIndexed(); // <======== CHANGED

  const material = new THREE.MeshBasicMaterial( { vertexColors: true, color: new THREE.Color('white') } );

  const mesh = new THREE.Mesh(geometry, material);
  const positionAttribute = mesh.geometry.getAttribute('position');
	const colors = [];
	const color = new THREE.Color('white');
		for (let i = 0; i < positionAttribute.count; i += 3) {
			colors.push(color.r, color.g, color.b);
			colors.push(color.r, color.g, color.b);
			colors.push(color.r, color.g, color.b);
		}
	mesh.geometry.setAttribute('color', new THREE.Float32BufferAttribute(colors, 3));
  scene.add(mesh);

const renderer = new THREE.WebGLRenderer({
  antialias: true
});
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
document.addEventListener('mousemove', onPointerMove, false); 

const controls = new THREE.OrbitControls(camera, renderer.domElement);

const highlightFace = color => {
    const { face } = intersected;
    const colorAttribute = intersected.object.geometry.getAttribute('color');

    colorAttribute.setXYZ(face.a, color.r, color.g, color.b);
    colorAttribute.setXYZ(face.b, color.r, color.g, color.b);
    colorAttribute.setXYZ(face.c, color.r, color.g, color.b);

    offset = ( face.a % 2 == 0 ) ? 3 : - 3; // <======== CHANGED
    colorAttribute.setXYZ(face.a + offset, color.r, color.g, color.b);
    colorAttribute.setXYZ(face.b + offset, color.r, color.g, color.b);
    colorAttribute.setXYZ(face.c + offset, color.r, color.g, color.b);
    
    colorAttribute.needsUpdate = true;
};


function onPointerMove(event) {

  event.preventDefault();

  mouse.x =...