CODEWITHSUNDEEP
javascriptoop
Don P
Don P

Reputation: 63567

Call a method of the same object

I have a js object with two functions. What is the right way to call mySecondFunction() from myFirstFunction()? Should it be this.mySecondFunction()? Or MyObject.mySecondFunction()?

I thought I would use "this", but if it is inside of an Event handler, then "this" refers to the DOM element and not to the object :(

var MyObject = {
  firstFunction: function() {
    whatgoeshere???.mySecondFunction();
  },

  secondFunction: function() {
    console.log('Hi!');
  }
}

Upvotes: 0

Views: 147

Answers (2)

Thalaivar
Thalaivar

Reputation: 23622

 var MyObject = {
  firstFunction: function() {
    this.mySecondFunction();
  },

  secondFunction: function() {
    console.log('Hi!');
  },
  mySecondFunction: function() {
    alert('Hi!');
  }
}

MyObject.firstFunction();

The above is what you intended to do. 

//declaring the constructor  
function MyObject() {  
    this.someProperty = 'whatever';        
}  
// declaring instance methods  
MyObject.prototype = {  
    firstFunction: function () {  
        this.secondFunction();  
    },  
    secondFunction: function () {  
        alert("Cool");  
    }  
};  

var am = new MyObject();    
am.firstFunction();

It's also a good idea to define the methods of your type using the prototype object, which is a property of the constructor function. The value of this will be the new object that you are trying to initialize.

Upvotes: 1

cutsoy
cutsoy

Reputation: 10251

In this case it's MyObject because it isn't an instance.

If you'ld have done something like:

var MyObject = function() {
};

MyObject.prototype.firstFunction = function() {
    this.secondFunction();
};

MyObject.prototype.secondFunction = function() {
    console.log('Hi!');
};

var instance = new MyObject();
instance.firstFunction();

Then, you create a new instance and can use this. In other words: the this refers to the current instance of an object

Upvotes: 0

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