update snippets 32-47

snippets/factorial.md

@@ -11,5 +11,8 @@ Throws an exception if `n` is a negative number.
 const factorial = n =>
   n < 0 ? (() => { throw new TypeError('Negative numbers are not allowed!') })()
   : n <= 1 ? 1 : n * factorial(n - 1);
-// factorial(6) -> 720
+```
+
+```js
+factorial(6) -> 720
 ```