jS OOP nested functions

Question

Ok this may be a noobolicious question as im new to OOP.

Im attempting to build something of a JS Object Library and was wondering if I could do it using nested functions??

var object = new function() {

    this.action1 = function () {
        this.dostuff1 = function () {
             return "dostuff1";
        };

     this.dostuff2 = function () {
          return "dostuff2";
     };                   
};

I am having trouble accessing the third level functions. Can I nest like this?

this.action2 = function () {
    return "action2";
}; 

alert(object.action1.dostuff2());

You can definitely create nested functions, but the problems you are having probably relate to use of the this keyword. Have you read up on how this works in JavaScript? It's a bit different to what happens in class-based OO languages like Java. — nnnnnn
– nnnnnn, Commented Oct 28, 2011 at 5:35

Juri · Accepted Answer · 2011-10-28 06:05:00Z

3

While Eberlin's answer is perfectly correct I'd suggest you to create a nested object which in turn again exposes functions rather than nesting functions itself. Otherwise this might become a maintainability nightmare.

Basically you could create

var Child = function(){
   //constructor
};

Child.prototype.doStuff2 = function(){
  return "dostuff2";
};

var Root = function(obj){
   //constructor
   this.child = obj;
};

Root.prototype.action1 = function(){
   return "doStuff1";
};

//usage
var myRoot = new Root(new Child());
myRoot.action1();
myRoot.child.action2();

Here's a live example: http://jsbin.com/ijotup/edit#javascript,live

answered Oct 28, 2011 at 6:05

Juri

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Comments

Adam Eberlin · Accepted Answer · 2011-10-28 05:42:15Z

See below for some code cleanup:

var o = (new function () {          // changed 'object' to 'o'
  this.action1 = (function () {     // added parentheses, not required.
    this.dostuff1 = (function () {  // does not return anything.
      return "dostuff1";            // and is also not the proper way to organize
    });                             // ** look at the javascript prototype
    return this;                    // now it does
  });                               // missing closing bracket

  this.dostuff2 = (function () {
    return "dostuff2";
  });                   
});

alert(o.action1().dostuff2());      // action1 is a function, not a variable.

Hope this helps. Also, here's a brief tutorial on the javascript prototype.

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