Question

Can anyone tell me why this code does not work?

PhoneNumber.prototype = Map;

var Map = {
    writeToDOM : function(container) {
        //DO STUFF HERE
    }   
};

PhoneNumber.writeToDOM(Container);

Is it not possible to reference an object in respect to an object’s protype and use said object’s functions? The reason I would want to do this is so I can use the Map variable on multiple objects rather than having to repeat the writeToDOM code for each object like this:

Object1.prototype.writeToDOM = function() {
    //DO STUFF HERE
}

Object2.prototype.writeToDOM = function() {
    //DO the exact same stuff as Object1
}

Answer 1

Your code is equivalent to the following:

var Map;
PhoneNumber.prototype = Map;

Map = {
    writeToDOM : function(container) {
        //DO STUFF HERE
    }   
};

PhoneNumber.writeToDOM(Container);

That is, you are assigning PhoneNumber.prototype to Map, which currently contains undefined. Then you are reassigning Map to a new value, but not changing PhoneNumber.prototype at all.

---

If you simply assigned Map to the desired object before assigning the prototype to Map, you would be OK:

var Map = {
    writeToDOM : function(container) {
        //DO STUFF HERE
    }   
};

PhoneNumber.prototype = Map;

PhoneNumber.writeToDOM(Container);