Accessing values of function object from within it's nested function

Question

Lets say we have function test():

function test(){
    a();

    this.b = function(){
        alert(1);
    }

    function a(){
        this.b();
    }
}

var t = new test();

This code will throw TypeError: this.b is not a function

The question is, how can we correctly access b() from within a()?

As I understand now there were 2 problems: this in a() wasnt reffering to test() and invocation of nested function that is using object's properties must be after declaration of these properties. — AlexTR
– AlexTR, Commented Apr 19, 2014 at 19:48

Barmar · Accepted Answer · 2014-04-19 19:33:46Z

2

Change the order:

function test(){
    var me = this;
    this.b = function(){
        alert(1);
    }

    a();

    function a(){
        me.b();
    }
}

You can't call this.b() before you've assigned the variable. And you need to use a local variable to capture the value of this in the closure.

answered Apr 19, 2014 at 19:33

Barmar

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Comments

phylax · Accepted Answer · 2014-04-19 19:33:28Z

0

function test(){
  var me = this;

  this.b = function () {
    console.log(1);
  }

  function a() {
    console.log('calling me.b()');
    me.b();
  }

  a();
}

var t = new test();
console.log('calling t.b()');
t.b();

answered Apr 19, 2014 at 19:33

phylax

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