Get name as String from a Javascript function reference?

Question

I want to do the opposite of Get JavaScript function-object from its name as a string?

That is, given:

function foo() {}  function bar(callback) {   var name = ???; // how to get "foo" from callback? }  bar(foo); 

How do I get the name of the function behind a reference?

Answer 1

If you can't use myFunction.name then you can:

// Add a new method available on all function values Function.prototype.getName = function(){   // Find zero or more non-paren chars after the function start   return /function ([^(]*)/.exec( this+"" )[1]; }; 

Or for modern browsers that don't support the name property (do they exist?) add it directly:

if (Function.prototype.name === undefined){   // Add a custom property to all function values   // that actually invokes a method to get the value   Object.defineProperty(Function.prototype,'name',{     get:function(){       return /function ([^(]*)/.exec( this+"" )[1];     }   }); } 

Answer 2

var name = callback.name; 

MDN:

The name property returns the name of a function, or an empty string for anonymous functions:

Live DEMO