Spotlight Follow Cursor
Spotlight target follows the mouse; tweak angle and penumbra.
JavaScript (plain)
const spot = new THREE.SpotLight(0xffffff, 2, 20, Math.PI / 6, 0.2, 1)
spot.position.set(2, 4, 2)
spot.castShadow = true
scene.add(spot)
scene.add(spot.target)
spot.target.position.set(0, 0.5, 0)