javascript function arguments as private variables

Question

I remember reading somewhere that function arguments get turned into private variables within the function so I tried this:

var node = function(nParent,nName,nContent){
    this.init = function(){
        alert(nName+" "+nParent+" "+nContent);
    }
};

var a = new node("A - parent","A - name","A - content");
var b = new node("B - parent","B - name","B - content");

a.init();
b.init();

which alerts the correct passed in arguments so is this ok to use instead of something like this:

var node = function(nParent,nName,nContent){
    var parent = nParent;
    var name = nName;
    var content = nContent;
    this.init = function(){
        alert(name+" "+parent+" "+content);
    }
};

I know I would have to use the second version if I wanted to do any form of extra validation checking on the arguments before assigning them to the private variables, I just didn't want to waste space if the arguments are already private variables that will never go anywhere, is this a reasonable thing to do? Thanks,

Did you mean to say alert(name+" "+parent+" "+content);

JaredPar
– JaredPar

2012-05-10 22:04:07 +00:00
Commented May 10, 2012 at 22:04 — JaredPar
– JaredPar, Commented May 10, 2012 at 22:04

Paul Bruno · Accepted Answer · 2012-05-10 22:01:11Z

5

Of course it's okay. These arguments are instantiated variables, with no appreciable difference from the other variables you set them to.

Now, if you didn't use any named parameters, and used arguments instead, then there would be a difference: in code readability, in even performance (there's a penalty for using arguments).

Only downside to all of this is that your variable definitions won't all be in the same place. (Assuming that there would be any more variable definitions and assignments in this function, beyond the params passed.)

answered May 10, 2012 at 22:01

Paul Bruno

1,9041 gold badge17 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

SLaks · Accepted Answer · 2012-05-10 22:00:51Z

0

Yes; that's perfectly fine.

answered May 10, 2012 at 22:00

SLaks

891k182 gold badges1.9k silver badges2k bronze badges

Collectives™ on Stack Overflow

javascript function arguments as private variables

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related