Classes?! No class Maximally Minimal Classes class SkinnedMesh extends THREE.Mesh { constructor(geometry, materials) { super(geometry, materials); this.identityMatrix = new THREE.Matrix4(); this.bones = []; this.boneMatrices = []; ... } update(camera) { ... super.update(); } } Instead of this mess function SkinnedMesh(geometry, materials) { SkinnedMesh.__super__.constructor .call(this, geometry, m