Initial data commit

Task/Flatten-a-list/JavaScript/flatten-a-list-4.js

@@ -0,0 +1,13 @@
+(function () {
+    'use strict';
+
+    // flatten :: Tree a -> [a]
+    function flatten(a) {
+        return a instanceof Array ? [].concat.apply([], a.map(flatten)) : a;
+    }
+
+    return flatten(
+        [[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
+    );
+
+})();