update snippets 32-47

snippets/flatten.md

@@ -5,6 +5,9 @@ Flattens an array.
 Use a new array and concatenate it with the spread input array causing a shallow denesting of any contained arrays.
 
 ```js
-const flatten = arr => [ ].concat(...arr);
-// flatten([1,[2],3,4]) -> [1,2,3,4]
+const flatten = arr => [ ].concat( ...arr );
+```
+
+```js
+flatten([1,[2],3,4]) // [1,2,3,4]
 ```