CODEWITHSUNDEEP
javascriptscope
chickpeas
chickpeas

Reputation: 443

variable scope inside object

myObject has two functions, the first one is calling the second one, is there a way to see variable a inside callMe()? 

var myObj =  {
   callMefirst: function() {
      var thisObj = this;
      var a;
      a = 'chocolate cookie';
      thisObj.callMe();
   },

   callMe: function() {
      alert(a);
   }
}
myObj.callMefirst();

otherwise I know I can pass it as a parameter, or set var a in global scope of the object but I'm interested to understand this specific case of scope

Upvotes: 0

Views: 3159

Answers (4)

HMR
HMR

Reputation: 39250

you can do this in multiple ways; the following uses closure.

var myObj = (function() {
   var a;

   return{
     callMefirst: function() {
        var thisObj = this;
        a = 'chocolate cookie';
        thisObj.callMe();
     },

     callMe: function() {
        alert(a);
     }
   }
})()
myObj.callMefirst();

Using closure with object initiation:

var myObjF = function(pass) {
   var a=pass;

   return{
     callMefirst: function() {
        var thisObj = this;
        thisObj.callMe();
     },

     callMe: function() {
        alert(a);
     }
   }
}
var myObj=myObjF("hello");
myObj.callMefirst();

Using function as object:

var myObjF = function(pass) {
   this.a=pass;

    this.callMefirst = function() {
        var thisObj = this;
        thisObj.callMe();
     };
}
myObjF.prototype.callMe = function() {
    alert(a);
}

var myObj=new myObjF("hello");
myObj.callMefirst();

Upvotes: 1

Mihail
Mihail

Reputation: 1479

Try this code:

var myObj =  {
  a:"",       
  callMefirst: function() {
      var thisObj = this;
      this.a = 'chocolate cookie';
      thisObj.callMe();
   },

   callMe: function() {
      alert(this.a);
   }
}
myObj.callMefirst();

Upvotes: 0

Xophmeister
Xophmeister

Reputation: 9211

a is defined within the callMefirst function and exists only here. Remember that JavaScript has functional (lexical) scope. As such, the easiest way to let callMe have access to a would to be as you suggest and define it within the scope of myObj.

Upvotes: 1

Quentin
Quentin

Reputation: 943207

No. Since it is defined with the var keyword, it is scoped to the function it is defined in. It is therefore only visible to that function and to other functions defined inside that function (of which you have none).

Upvotes: 2

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