How can I execute recursion regardless of the function name?

Question

Possible Duplicate:
Can I get the name of the currently running function in javascript?

I need this for recursion. I'd like to be able to change the function name without checking and changing every instance where the function calls itself.

(For example php has "magic constants" like __FUNCTION__ etc.. - is something similar in JavaScript?)

Actually this question is slightly different, since he wants a reference to the function and not really the name. The name alone does not help him for recursive calls... Hence: No **exact duplicate**. — Ferdinand Beyer, Jul 01 '11 at 14:07
there's already an answer to this question... [See Here](http://stackoverflow.com/questions/1013239/can-i-get-the-name-of-the-currently-running-function-in-javascript) — El Guapo, Jul 01 '11 at 13:41
@Ferdinand Agreed. "alert the name of the function" and "have the function call itself without using its name at all" are quite different problems. +1 to your answer as well; I actually prefer it to my own :) — David Ruttka, Jul 01 '11 at 19:27

David Ruttka · Accepted Answer · 2011-07-01T14:06:44.307

If your goal is recursion, you don't need the function name as a string if you can get a reference to the function itself. Note that you'll still have to check and change every instance where the function is called by others, and that's likely to be a larger task than updating the recursive calls (if for no other reason than it's not localized to the function body).

Passing the function as an argument

function foo(self, i)
{
    if (i === 0 )
        return;

    console.log(i--);
    self(self, i);
}

foo(foo, 3);

Using arguments.callee (As Raynos points out, this is brittle in strict mode)

function foo(i)
{
    if (i === 0 )
        return;

    console.log(i--);
    arguments.callee(i);
}

foo(3);

Output of either option

3
2
1

Ferdinand Beyer · Answer 2 · 2011-07-01T14:24:01.510

Maybe you can refactor your function since arguments.callee is not dependable. For example, you could use a nested function that does the recursion:

var name_does_not_matter = function(m) {
    var inner = function(n) {
        if (n <= 2) return 1;
        return inner(n-2) + inner(n-1);
    };
    return inner(m);
};

[UPDATE] Actually, you should be able to access the function by its name regardless of the parent scope. In my test, the following example works:

var foo = 10;
var bar = function foo(n) {
    return (n <= 2) ? 1 : foo(n-2) + foo(n-1);
};
alert(foo);  // Displays '10'
alert(bar(10));  // Displays '55'

score 0 · Answer 3 · answered Jul 01 '11 at 13:43

0

function senad()
{
  var fName= arguments.callee.toString();
            fName= fName.substr('function '.length);       
            fName= fName.substr(0, fName.indexOf('('));  
            alert(fName)
}
senad();

answered Jul 01 '11 at 13:43

Senad Meškin

13,597
4
37
55

score 0 · Answer 4 · answered Jul 01 '11 at 13:47

0

(function() { 
  "use strict"; 
  console.log(arguments.callee); 
})()

Yields

TypeError: Cannot access property 'callee' of strict mode arguments

You cannot do this in ES5 strict mode, and for a good reason. It's a hack. Don't do it.

answered Jul 01 '11 at 13:47

Raynos

166,823
56
351
396

How can I execute recursion regardless of the function name?

4 Answers4