JavaScript-Functional programming

Object nature of functional programming for javascript:  
Function a ()  
{ 
    var x= " Sth ";   
     return b () { 
         //do with x; 
     } 
} 
var  c = a ();  
equivalent to  
Function a ()  
{ 
         this.x =  "Dosth";  
         This.b = function () { 
               //do with this.x 
        } 
} 
Var c = new a ();  

But  
1) functional programming instinctively avoids the construction of useless objects  
Because functional programming encourages closure construction when used with closures, object-oriented objects are usually constructed in advance and ready to be there.
2) Functional programming to protect the private variable  
x will not be accessed externally outside of the packet  
3) Closures and objects should be aware of releasing resources  

such as: c = null; SetTimeout (collectgarbage,100);

JavaScript-Functional programming