oops in javascript : call one method from another?

Question

I am trying to manage my code in javascript.What I have done is created two classes.

(function(){
 Main1 = function(){
    return this;
  }

Main1.prototype = {
Main1_method1 : function(){

},
Main1_method2 : function(){

}
}


})();

(function(){
 Main2 =function(){
        return this;
      }

    Main2.prototype = {
    Main2_method1 : function(){

    },
    Main2_method2 : function(){

    }
    }
})();

var MyInstance1 = new Main1();
var MyInstance2 = new Main2();

Question : I want to invoke one method in another.I want to call Main2_method1 in Main1_method1,but i have no idea how to do it.

I can use the classical model(function.prototype.method = function(){}) or the prototypal model(object.create).But I want to do this using the above method.

As all your functions are missing the var keyword, they are global and should be accessible from anywhere, as long as they are defined when you intend to use them. — adeneo, Dec 18 '13 at 18:28
@adeneo:..Using var would have made my code even more complicated ? and is it a good way to code — HIRA THAKUR, Dec 18 '13 at 18:42
http://stackoverflow.com/questions/8862665/what-does-it-mean-global-namespace-would-be-polluted — isherwood, Dec 18 '13 at 18:54

Simon Boudrias · Answer 1 · 2013-12-18T20:05:59.847

0

Well, you'll need to call the method on the instance:

(function(){
    Main2 =function( instance1 ) {
        this.main1 = instance1;
        return this;
     }

    Main2.prototype = {
        Main2_method1 : function() {
            this.main1.Main1_method1();
        }
    }
})();

var MyInstance1 = new Main1();
var MyInstance2 = new Main2( MyInstance1 );

The only part you need to figure out is how Main2 access the Main1 instance. You can simply put it globally which will work.

But to be clean, you'd probably want to inject Main1 instance inside Main2 on instantiation. Or, you keep them decoupled using an event hub.

edited Dec 18 '13 at 20:05

answered Dec 18 '13 at 19:51

Simon Boudrias

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dint understand...is this a correct way to do things?suppose if it was var Main1 and var Main2 – HIRA THAKUR Dec 18 '13 at 19:57
Simply understand you need to call the method on the instance like so: `MyInstance1.Main1_method1()` – Simon Boudrias Dec 18 '13 at 19:58
After that, you need to make sure the `Main2` class can access the `MyInstance1` variable. And to this end, I listed some pattern you should use to keep your code clean and maintainable. – Simon Boudrias Dec 18 '13 at 20:00
MyInstance1.Main1_method1() this is how you access methods in classical and prototypal models,i know about this...but how can i do that in my above code.. – HIRA THAKUR Dec 18 '13 at 20:03
Inject it in `Main2` at initialization -> `var MyInstance2 = new Main2( MyInstance1 );` – Simon Boudrias Dec 18 '13 at 20:04
Edited my answer with complete code for injecting the instance. – Simon Boudrias Dec 18 '13 at 20:06

score 0 · Answer 2 · answered Dec 18 '13 at 20:44

I'm not sure that understood what you need and not sure that you understand it yourself ))

But if I understood you correctly... ))

(function(){

    Main1 = function(){return this};

    Main1.prototype = {
        method1 : function(){this.method1()}
    };

}());

(function(){

    Main2 = function(){return this};

    Main2.prototype = {
        method1 : function(){console.log('Eh?')}
    };

}());

var MyInstance1 = new Main1();
var MyInstance2 = new Main2();

MyInstance1.method1.call(MyInstance2);

score -1 · Answer 3 · answered Dec 18 '13 at 19:54

Inspired in the book "Javascript Patterns" by Stoyan Stefanov, you can use the "Public static Members" pattern, which allows you to define some special methods for an object accessible from everywhere. See that example:

    // Define a first object
    var Main1 = function(){
      var method1 = function() {
        return 'Main1.Method1';
      }

      var method2 = function(){
        return "I'm Main1 method2, executing: " + Main2.Method1();
      }

      return {
        Method1 : method1,
        Method2 : method2
      }
    }

    // Define a second object
    var Main2 = function(){
      var method2 = function() {
        return 'Main2.Method1';
      }
      return {
        Method2 : method2
      }
    }
    // Add a static method to Main2
    Main2.Method1 = function(){
      return 'Main2.Method1';
    }

    // Then you can execute the static method without 
    // instantiate its object...
    console.log(Main2.Method1()); // output: Main2.Method1

    // So, this will work
    var foo = new Main1();
    console.log(foo.Method2()); //output: I'm Main2 Method2, executing: Main2.Method1

There is not the only one solution, but in my opinion it is one of the best.

Back in your code, perhaps the problem is that you have defined the two objects in separate closures. So Main1 cannot use Main2 methods because of Main2 have been defined in a diferent scope.

oops in javascript : call one method from another?

3 Answers3