Question

I am coming at Javascript from a classical OOP background and am having trouble with understanding the prototype.

Given the code example below:

1. How would I call/execute bar in foo?
2. why use the “privileged” function instead of putting it on the prototype?

3. This is probably answered in Q1 but can bar1 and bar2 call each other?

   function foo()
       {
          this.property = "I'm a property";
   
          this.privileged = function()
          {
             // do stuff
          }
       }
   
       foo.prototype.bar = function()
       {
          // do stuff
       }
   
       foo.prototype.bar2 = function()
       {
          // stuff
       }
   

Answer 1

There’s a lot of FUD about this to this day.

1). Simple usage:

var xxx = new foo();  // Create instance of object.
xxx.privileged();  // Calls the internal closure.
xxx.bar();  // First looks for internals, then looks to the prototype object.

2). This basically creates a closure that can only be modified on the instance. Not a private at all (since anything can talk to it through the object instance), but rather an individual copy of a function, where each instance of the object gets a new copy of the function. You can alter the function itself, but you cannot alter it globally. I’m not a big fan of this method of creating things.

3). Yes:

foo.prototype.bar = function(){
    this.bar2();
}

foo.prototype.bar2 = function(){
    this.bar();
}
// Although... NEVER do both.  You'll wind up in a circular chain.

For edification, I built you a fiddle which should help show how things get called:
http://jsfiddle.net/7Y5QK/