4
\$\begingroup\$

Is this the best way to get access to the parent scope when dealing with complex objects literals?

I find this a bit ugly, and obviously the best solution would never be involving calling it by name directly, but by saving the state of the previous scope. I tried it with bind() but didn't get it to work properly.

var object = {
　　name : 'foo',
　　getName : (function(){
　　　　　 return function(that){ 
            return {
                a : 111,
                b : that.name,
                c : function(){
                    return this.b;
                }
            }
       }(this);
 　})
};

object.getName().b  // 'foo'
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1 Answer 1

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I understand that you are just experimenting with closures, because your code should be a simple geter like that... 

var object = {
　　name : 'foo',
　　getName : function(){ //closure
        return {
            a : 111,
            b : this.name, // variable th is avaliable in the inner scope
            c : function(){
                return this.b;
            }
        }
 　}
};

object.getName().b  // 'foo'

This does the same as your example:

var object = {
　　name : 'foo',
　　getName : (function(){ //closure
         var th=this;     // a new var introduced in a closure
　　　　　 return function(){ 
            return {
                a : 111,
                b : th.name, // variable th is avaliable in the inner scope
                c : function(){
                    return this.b;
                }
            }
       }();
 　})
};

object.getName().b  // 'foo'

[edit]

this in JS depends on where the function is called as well, so if you want a nice encapsulation Try this:

var object = {}
(function(){

  var _name='foo';

  object.getName=function(){
    return _name;
    }
});
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4
  • \$\begingroup\$ is it possible to make 'getName' an object by itself that has access to the parent object, without the need to invoke the function on every call? \$\endgroup\$ Commented Jun 26, 2011 at 12:32
  • \$\begingroup\$ There are at least two totally different ways (except yours) to do it. But I still don't see why getName should be an object. It looks like a simple getter function and it should be one. \$\endgroup\$ Commented Jun 26, 2011 at 13:30
  • \$\begingroup\$ this is just an example code, and it seems that i picked the wrong names.. lets call it 'a' and 'b' then, instead of 'name' and 'getName' \$\endgroup\$ Commented Jun 26, 2011 at 13:37
  • \$\begingroup\$ Then I'd say that my second example - caching the correct this in a variable and managing its scope - suits your case. But i don't recommend using this keyword and trying to simulate object-oriented coding in JS. It might hurt some day. \$\endgroup\$ Commented Jun 26, 2011 at 14:26

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