Access JavaScript object variable from function

Question

I have the following code below, but one problem. I want to access a variable from inside the function clslevel() named the_id, from the calling anonymous function. I tried this.the_id but it returns undefined.

function clslevel(id){ 
  var the_id = id;
  this.methodOne=function(param){
    param();
    return this;
  };
  this.methodTwo=function(param){
    param();
    return this;
  };
  
}


function level(id){
  return new clslevel(id);
}



level("myButton")
  .methodOne(
    function(){
      console.log("methodOne called.");
      // how can I access the variable 'the_id' in clslevel() from here?
    }  
  )
  .methodTwo(
    function(){
      console.log("methodTwo called");
    }  
  )

thank you in advance!

You can't. Absolutely. That's how scope works. What problem are you actually trying to solve? — Robin Zigmond
– Robin Zigmond, Commented Nov 2, 2018 at 12:44

omri_saadon · Accepted Answer · 2018-11-02 12:45:18Z

2

Pass it as a parameter to the function, like this:

function clslevel(id){ 
  var the_id = id;
  this.methodOne=function(param){
    param(the_id);
    return this;
  };
  this.methodTwo=function(param){
    param();
    return this;
  };
  
}


function level(id){
  return new clslevel(id);
}



level("myButton")
  .methodOne(
    function(the_id){
      console.log("methodOne called.", the_id);
      // You have the_id here
    }  
  )
  .methodTwo(
    function(){
      console.log("methodTwo called");
    }  
  )

answered Nov 2, 2018 at 12:45

omri_saadon

10.7k8 gold badges36 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Georgy · Accepted Answer · 2018-11-02 12:45:26Z

2

You can pass this variable into callback:

function clslevel(id){ 
  var the_id = id;
  this.methodOne=function(param){
    param(the_id);
    return this;
  };
  this.methodTwo=function(param){
    param();
    return this;
  };

}


function level(id){
  return new clslevel(id);
}



level("myButton")
  .methodOne(
    function(passed_id){
      console.log("methodOne called.");
      console.log(passed_id)
      // how can I access the variable 'the_id' in clslevel() from here?
    }  
  )
  .methodTwo(
    function(){
      console.log("methodTwo called");
    }  
  )

answered Nov 2, 2018 at 12:45

Georgy

2,4623 gold badges23 silver badges35 bronze badges

Comments

Luis felipe De jesus Munoz · Accepted Answer · 2018-11-02 12:48:32Z

1

You can pass a reference of your object so you can use the parent functions inside the other scope

function clslevel(id){ 
  this.the_id = id;
  this.methodOne=function(param){
    param(this);
    return this;
  };
  this.methodTwo=function(param){
    param(this);
    return this;
  };
  
}


function level(id){
  return new clslevel(id);
}



level("myButton")
  .methodOne(
    function(parent){
      console.log("methodOne called.");
      console.log('the_id = ' + parent.the_id)
      // how can I access the variable 'the_id' in clslevel() from here?
    }  
  )
  .methodTwo(
    function(){
      console.log("methodTwo called");
    }  
  )

answered Nov 2, 2018 at 12:48

Luis felipe De jesus Munoz

8,0133 gold badges38 silver badges54 bronze badges

Collectives™ on Stack Overflow

Access JavaScript object variable from function

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related