Kata

Create a function generator genfib() that returns a function fib() which always returns the next fibonacci number on each invocation (and returns 0 when being called the first time).

Example:

var fib = genfib();
fib(); // -> returns 0
fib(); // -> returns 1
fib(); // -> returns 1
fib(); // -> returns 2

fib = genfib()
fib() # -> returns 0
fib() # -> returns 1
fib() # -> returns 1
fib() # -> returns 2