Using a mix of prototypal inheritance and copying properties

When you use inheritance, you will most likely want to take already existing functionality and then build upon it. This means creating a new object by inheriting from an existing object and then adding 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 use an existing object as a prototype of a new one

• Copy all of the properties of another object into the newly created one

  function objectPlus(o, stuff) {
  var n;
  function F() {}
  F.prototype = o;
  n = new F();
  n.uber = o;
  
  for (vari 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 methods and properties that are to be copied. Let's see this in action.

Start with the base shape object:

var shape = {
name: 'Shape',
toString: function () {
return this.name;
}
};

Create a 2D object...