How to get the the variable name from within a function in this example:
// it should return A
var A = function(){ console.log(this.name); }
No, there is nothing like that in Javascript. That function is anonymous, so it has no name, and what you want is ambiguous because the function could just as easily have any number of variables referencing it like:
var a, b, c, d;
a = b = function(){ console.log(this.name); };
c = b;
d = c;
a = b = 5;
// a and b no longer refer to the function, but c and d both do
What is it you are actually trying to accomplish? I'm sure there is another way to achieve it.