Passing function to other prototype

Question

Passing function to other prototype

I have below code

var Callback = function(op) {
    this.callback = op.callback;
}

var Test = function (op) {
  for (var option in op) {
    if (!this[option]) this[option] = op[option];
  }

}

Test.prototype.init = function(bb) {
    console.log('aa = ' + this.aa);
    console.log('bb = ' + bb);

    if (bb < 3) {
        this.init(bb + 1);
    } else {
        this.callback;
    }
}

var finalCallback = function() {
    console.log('this is finalCallback');
}

var myCallback = new Callback({
    callback: finalCallback
});

var myTest = new Test({
    aa: 1,
    callback: myCallback
});

myTest.init(1);

Line 19 didn't print 'this is finalCallback' AT ALL because this.callback; got executed but it doesn't point to a function. But the below works:

myTest.init(1);
myCallback.callback();

I guess when passing myCallback to myTest, it didn't pass finalCallback??

Can someone help to explain this behavior and how to fix it?

javascript
node.js
javascript-framework
javascript-module

Answer 1

this works:

var myTest = new Test({
    aa: 1,
    callback: myCallback.callback()
});

I assume this is the bit you mean. If not, please clarify what is not printing.

this doesn't work, because it is only a reference - an assignment.

  callback: myCallback

this is what executes it ()

so:

callback: myCallback.callback;

then:

this.callback();

I apologize if I am not succinct enough. I hope I am understanding what you are asking.

Answer 2

seems you want to make this (use op.callback as function ):

var Callback = function (op) {
    this.callback = op.callback;
    return this.callback;
};

and functions should be invoked with ()

 } else {
        this.callback();
  }

http://jsfiddle.net/oceog/SashU/3/

this is example where it can be used

Answer 3

As has been pointed out, you're not even trying to invoke this.callback on line 19. Invoke it with parentheses.

Even then, it doesn't work. When you do var myTest = new Test({ aa: 1, callback: myCallback });, myCallBack isn't a function; it's an object with a property callback. Change line 19's this.callback to this.callback.callback() to invoke that function. One line 19, this.callback is an instance of Callback—an object with a property callback that is a function.

http://jsfiddle.net/trevordixon/SashU/4/ shows a working example.