Can I get the name of the currently running function in JavaScript?

Can I get the name of the currently running function in JavaScript?

Is it possible to do this:
myfile.js:
function foo() {
alert();
// pops-up “foo”
// or even better: “myfile.js : foo”
}

I’ve got the Dojo and jQuery frameworks in my stack, so if either of those make it easier, they’re available.

Solutions/Answers:

Solution 1:

You should be able to get it by using arguments.callee.

You may have to parse out the name though, as it will probably include some extra junk. Though, in some implementations you can simply get the name using arguments.callee.name.

Parsing:

function DisplayMyName() 
{
   var myName = arguments.callee.toString();
   myName = myName.substr('function '.length);
   myName = myName.substr(0, myName.indexOf('('));

   alert(myName);
}

Source: Javascript – get current function name.

Solution 2:

For non-anonymous functions

function foo()
{ 
    alert(arguments.callee.name)
}

But in case of an error handler the result would be the name of the error handler function, wouldn’t it?

Solution 3:

All what you need is simple.
Create function:

function getFuncName() {
   return getFuncName.caller.name
}

After that whenever you need, you simply use:

function foo() { 
  console.log(getFuncName())
}

foo() 
// Logs: "foo"

Solution 4:

According to MDN

Warning: The 5th edition of ECMAScript (ES5) forbids use of arguments.callee() in strict mode. Avoid using arguments.callee() by either giving function expressions a name or use a function declaration where a function must call itself.

As noted this applies only if your script uses “strict mode”. This is mainly for security reasons and sadly currently there’s no alternative for this.

Related:  Is there a better way to do optional function parameters in JavaScript? [duplicate]

Solution 5:

This should do it:

var fn = arguments.callee.toString().match(/function\s+([^\s\(]+)/);
alert(fn[1]);

For the caller, just use caller.toString().

Solution 6:

This has to go in the category of “world’s ugliest hacks”, but here you go.

First up, printing the name of the current function (as in the other answers) seems to have limited use to me, since you kind of already know what the function is!

However, finding out the name of the calling function could be pretty useful for a trace function. This is with a regexp, but using indexOf would be about 3x faster:

function getFunctionName() {
    var re = /function (.*?)\(/
    var s = getFunctionName.caller.toString();
    var m = re.exec( s )
    return m[1];
}

function me() {
    console.log( getFunctionName() );
}

me();