What is the proper jargon to refer to a variable wrapped inside a function closure?

Question

In JavaScript, there is no such thing as a "private" variable. In order to achieve encapsulation and information hiding in JavaScript, I can wrap a variable inside a function closure, like so:

var counter = (function() {    
    var i = 0;
    var fn = {};
    fn.increment = function() { i++; };
    fn.get = function() { return i; };
    return fn;
{)();    
counter.increment();
counter.increment();
alert(counter.get()); // alerts '2'

Since I don't call i a private variable in JavaScript, what do I call it?

`s/fn/counter/` outside of the outer anonymous function. – Apr 04 '12 at 19:42 — , Apr 04 '12 at 19:42

score 7 · Accepted Answer · answered Apr 04 '12 at 19:56

7

According to wikipedia they're called "upvalues".

A closure allows a function to access variables outside its immediate lexical scope. An upvalue is a free variable that has been bound (closed over) with a closure. The closure is said to "close over" its upvalues.

Although it's probably better to wrongly call them private variables so people will understand what you mean.

answered Apr 04 '12 at 19:56

Esailija

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You could also just call it a free variable – Raynos Apr 04 '12 at 19:58

What is the proper jargon to refer to a variable wrapped inside a function closure?

1 Answers1