Merge pull request #60 from benhanks040888/master

Check for array length in tail function to return the correct value f…

README.md

@@ -515,8 +515,9 @@ Use array destructuring to swap values between two variables.
 Return `arr.slice(1)`.
 
 ```js
-const tail = arr => arr.slice(1);
+const tail = arr => arr.length > 1 ? arr.slice(1) : arr;
 // tail([1,2,3]) -> [2,3]
+// tail([1]) -> [1]
 ```
 
 ### Unique values of array