Great post. I love the idea of cows and fences - I have a feeling I'm going to be picturing those cows in their fence every time I write a function now haha!

Awesome explanation, but I think you made a mistake here :

the code above doubles the number in the array and logs it in the console. . .

Here is how variable sum will be logged

 function doubleThaNumbers(){
    const digits = [1,2,3,4,5,6];
    const sum = digits.map(function(n){
                  return n*2
                })
    console.log(sum)
 }

doubleThaNumbers()