JavaScript-Functional programming

The object nature of JavaScript's functional programming:
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 the use of closures to call closure constructs, Object-oriented objects are usually constructed in advance and ready to be there.
2) Functional programming protects private variables
x will not be accessed outside the packet except the closure
3) Closures and objects should pay attention to releasing resources

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

JavaScript-Functional programming