potree-sdk/src/PointCloudTree.js

import * as THREE from "../libs/three.js/build/three.module.js"; 

export class PointCloudTreeNode extends THREE.EventDispatcher{

	constructor(){
		super();
		this.needsTransformUpdate = true;
	}

	getChildren () {
		throw new Error('override function');
	}

	getBoundingBox () {
		throw new Error('override function');
	}

	isLoaded () {
		throw new Error('override function');
	}

	isGeometryNode () {
		throw new Error('override function');
	}

	isTreeNode () {
		throw new Error('override function');
	}

	getLevel () {
		throw new Error('override function');
	}

	getBoundingSphere () {
		throw new Error('override function');
	}
};

export class PointCloudTree extends THREE.Object3D {
	constructor () {
		super();
        //this.spriteGroup = new THREE.Object3D  //add
	}

	initialized () {
		return this.root !== null;
	}
};