Remove unneeded line

the line " if (n === 0) return 1 " can be omitted, because the ' product = 1 ' and the loop won't run if  'n = 0'  and the returning result will be '1'

calculator/calculator.js

@@ -21,7 +21,6 @@ const power = function(a, b) {
 };
 
 const factorial = function(n) {
-  if (n === 0) return 1;
   let product = 1;
   for (let i = n; i > 0; i--) {
     product *= i;