Linting

snippets/flatten.md

@@ -5,6 +5,6 @@ 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 );
+const flatten = arr => [ ].concat(...arr);
 // flatten([1,[2],3,4]) -> [1,2,3,4]
 ```