扩展THREE.js“类”时，为什么需要从新对象内调用.call（this）方法？

Question

I'm creating an object that I want to inherit from THREE.Object3D(). My code is as follows:

function myNewObject() {
  THREE.Object3D.call(this);

  //...

}

myNewObject.prototype = new THREE.Object3D();
myNewObject.prototype.constructor = myNewObject;

My question is: why do I need to invoke 'THREE.Object3D.call(this)' from within myNewObject()? Isn't it enough that I'm assigning the prototype to a THREE.Object3D() object?

Answer 1

This is typical Javascript subclassing, though you should really call:

THREE.myNewObject.prototype = Object.create( THREE.Object3D.prototype );
THREE.myNewObject.prototype.constructor = THREE.myNewObject;

rather than new THREE.Object3D()