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];
    }
  });
}