Objects extended in ExtJS

If you try to extend Object with ExtJS and add some properties to the new class:

 MyClass = Ext.extend(Object, {
   p: 1
 }

When you will create a new instance of this class, you loose all your properties previously added.

 var obj = new MyClass ();
 console.log(obj.p); // will be 'undefined'

This is the issue:

 MyClass = Ext.extend(Object, {
   constructor : function(options){
     Ext.apply(this, options || {} );
   },
   p: 1
 });

And to extend again:

 MySecondClass = Ext.extend(MyClass, {
   constructor : function(options){
     //call the base constructor
     MyClass.superclass.constructor.call(this, options);
     this.r = this.q + this.p;
   },
   q: 2
 });