Is it possible to get the name of an anonymous JavaScript function?

In the use-case that you're trying, it's possible that there can be more than one variable holding the same anonymous function.

ie, it can go on like:

var F = function(){}; var x = new F(); var x2 = x; var x3 = x; var blah = x3; 

So, now we have more than one name to look for. And the first thing I thought of is to loop through all the objects under window and print their name which is having the same method as the value.

So, you'd think of something like:

for each (item in window){ if (myfunc == item){ console.log(/*Somehow print the actual name of the item */) } } 

But, it doesn't work that way since, now item is another variable, and look like there is no built-in property that gives the variable name. May be, have a look at Variable name as a string in Javascript , not that it helps here, though...

So, finally, since you mentioned you're trying to do error logging, thought of using stack-traces. Don't know if it will apply in your situation, may be still a bit enlightening :)

And this is how it goes: (To be warned, this is a hack)

var myFunction = function(){ var err = new Error(); console.log(err.stack) } myFunction(); 

will output something like:

myFunction@debugger eval code:3:17 @debugger eval code:6:5 @debugger eval code:1:15 

And, taking that to the next level:

var myFunction = function(){ var err = new Error(); console.log(err.stack.split("@")[0]) /* split the stack-trace string and get the first word before @ */ } myFunction(); 

Now, the output for that will be:

myFunction 

Which, indeed is the name of the variable that is holding the anonymous function.

Note: This answer is inspired by the question How can I get a Javascript stack trace when I throw an exception?

Have tried this only in Firefox, there's a chance the stack-trace might be different elsewhere.

Edit: Failed to notice your edit, this might need editing of declarations, which breaks your use-case. :(