Is it possible in Javascript to get the name of a variable?

Question

I know this is completely useless, but I'm nonetheless curious. Is it possible to do something like the below?

function getVariableName ( v )
{
    // .... do something ..... 
    // return the string "v" 
}
var x = 69;
var y = "somestring";
console.log(getVariableName(x)); // prints "x" to the console
console.log(getVariableName(y)); // prints "y" to the console

No, you cannot do that. The mention of `x` in the calling environment results in the *value* of `x` being passed, and a value is just a value; it has no intrinsic relationship to the variable. — Pointy, Apr 09 '15 at 17:35
I couldn't help but wonder, why would you ever want to do that? — php_nub_qq, Apr 09 '15 at 17:35
I see the question has been closed, however here's an additional solution `console.log(Object.keys({x:null})[0]);` where you put the variable name where `x` is. — php_nub_qq, Apr 09 '15 at 17:46

score -2 · Answer 1 · answered Apr 09 '15 at 17:35

-2

function getArgNames(fn) {
    var matches = fn.toString().match(/\(([a-z_, ]+)\)/i);
    if (matches.length > 1) {
        return matches[1].replace(/\s+/g, '').split(',');
    }
    return [];
}

That will return an array of the names of all arguments passed in to the function.

answered Apr 09 '15 at 17:35

Randy Hunt

435
3
10

1

This returns the *formal* parameter names - the names from the function definition. The OP wants the names of variables referenced in calls to the function - the *actual* parameters. – Pointy Apr 09 '15 at 17:36
Ah, right. It satisfied the "V" example, but not the X and Y conditions. :-/ – Randy Hunt Apr 09 '15 at 17:38

Is it possible in Javascript to get the name of a variable?

1 Answers1