CODEWITHSUNDEEP
javascriptobject
Abdi
Abdi

Reputation: 499

How to call a method within an object

I'm trying to create a property within an object and I want the value to be whatever is returned from a method within the same function: 

var model = {
  generateRandomNumber: function(){
      var randomNumber = Math.floor(Math.random() * 101);
      return randomNumber;  
  }, 

  generatedNumber: this.generateRandomNumber()
};

But I get an error: Uncaught TypeError: undefined is not a function

I just want to have the new property to contain whatever is returned from the method within the same object.

Upvotes: 1

Views: 70

Answers (3)

Liam MacDonald
Liam MacDonald

Reputation: 301

Your problem is with your referencing, using this.generateRandomNumber inside an object.. that won't work. Why not just do this:

var model = {
  generateRandomNumber: function() {return Math.floor(Math.random()*101;}, generatedNumber: Math.floor(Math.random()*101};

This would have the same effect.

Upvotes: 0

instanceofnull
instanceofnull

Reputation: 1071

The function generateRandomNumber is not accessible within the object declaration because the object literal hasn't been fully parsed. Try this:

var obj = {
    generateRandomNumber: function() {
        return this.generatedRandomNumber = Math.floor(Math.random() * 101);
    }
}

obj.generateRandomNumber();
alert(obj.generatedNumber);

Upvotes: 0

Quentin
Quentin

Reputation: 943108

You can't access the object (to call the function) until after the object exists.

You have to do this in two steps:

 var model = {
    generateRandomNumber: function(){
        var randomNumber = Math.floor(Math.random() * 101);
        return randomNumber;  
    }
};

model.generatedNumber = model.generateRandomNumber()

Since the method doesn't depend on this (which begs the question of why it is an object method in the first place), you could define the function separately instead.

function generateRandomNumber (){
    var randomNumber = Math.floor(Math.random() * 101);
    return randomNumber;  
}

var model = {
    generateRandomNumber: generateRandomNumber,
    generatedNumber: generateRandomNumber()
};

Upvotes: 4

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