B extends A, but B.add populates A.prototype.property

Question

I have one class and another that inherits property children from the first one.

function A() {}
A.prototype.children = [];

function B() {}
B.prototype = ne         


        

Answer 1

You shouldn´t be using the prototype to store data that is for the instance. When you do this.children, there are no children in B, thus the prototype chain continues to A. As suggested by @Bergi, you should remove:

B.prototype = new A

Try defining:

function A() {
  this.children = [];
}
A.prototype.addChild = function (o) { this.children.push(o)};
var b = new A();
b.addChild({});