ExtJs inheritance behaviour

Question

Can someone please explain this behavior to me. Lets declare a class:

Ext.define('baseClass',{
    a:null,
    ar:[],

    add:function(v) {
        this.ar.push(v);
    },
    sayAr:function() {
        console.log(this.ar);
    },

    setA:function(v) {
        this.a= v;
    },
    sayA:function() {
        console.log(this.a);
    }
});

Now I create two objects

var a = Ext.create('baseClass');
var b = Ext.create('baseClass');

Test the property

a.setA(1);
b.setA(2);

a.sayA();
b.sayA();

This outputs

1
2

Everything is OK, but

a.add(1);
b.add(2);

a.sayAr();
b.sayAr();

We get

[1,2]
[1,2]

This I don't understand. Why does it use separate "a" properties but one "ar" array for both objects. "ar" is not declared as static! I don't get it at all.

ExtJs inheritance behaviour

2 Answers