// Little background about unknown properties
var myObject = Ember.Object.create({name: 'hi'}); # a plain simple ember object

// so the property "name" is a known property for myObject, but any other properties which are not defined on this object are unknown properties
myObject.get("age"); // age is an unknown property as we did not set "age" yet, the expression on the left evaluates to undefined

// Be careful ! only properties on the object that are not "set" yet are unknown properties but not the properties that evaluate to null/undefined
myObject.set("status", undefined); // although myObject.get("status") evaulates to undefined, status is a known property for myObject

// unknownProperty hook
// Basically when we do a "get" on a unknown property, instead of returning undefined the result of the unknownProperty hook is returned
var hookedObject = Ember.Object.create({
  name: 'hi',
  unknownProperty: function(key) {
    return key+" is an unknown property";
  }
});

hookedObject.get("name"); // => hi
hookedObject.get("randomKey"); // => randomKey is an unknown property
hookedObject.get("age"; // => age is an unknown property
hookedObject.set("age", 22); // age is now  a known property
hookedObject.get("age"); // => 22

// setUnknownProperty hook
// it gets called when we are trying to do a set on an unknown property
var baseObject = Ember.Object.create();
var hookedObject = Ember.Object.create({
  setUnknownProperty: function(key, value){
    baseObject.set(key, value);
  }
});
hookedObject.set("name", "Bruce");
baseObject.get("name"); // => Bruce

// We are basically proxying the set property to other object, Reminds you of something ?...Enter Ember.ObjectProxy
//   `Ember.ObjectProxy` forwards all properties not defined by the proxy itself
//    to a proxied `content` object. (from the source code)
// Let's implement a similar proxy object of our own using the above concepts
var myProxyObject = Ember.Object.create({
  unknownProperty: function(key){
    var content = this.get("content");
    if(content){
      return content.get(key);
    }
  },
  setUnknownProperty: function(key, value){
    var content = this.get("content");
    if(content){
      return content.set(key, value);
    }else{
      // raise an error saying cannot set key, value as the content property is undefined
    }
  }
})