Object-Oriented JavaScript

Using a Mix of Prototypal Inheritance and Copying Properties

When you use inheritance, you will most likely want to take some existing functionality and then build upon it. This means creating a new object by inheriting from an existing object and then adding some additional methods and properties. You can do this with one function call, using a combination of the last two approaches just discussed.

You can:

• Use prototypal inheritance to clone an existing object
• Copy all of the properties of another object

  function objectPlus(o, stuff) {
    var n;
    function F() {}
    F.prototype = o;
    n = new F();
    n.uber = o;
  
    for (var i in stuff) {
      n[i] = stuff[i];
    }
    return n;
  }

This function takes an object o to inherit from and another object stuff that has the additional ...