Initial data commit

Task/Flatten-a-list/JavaScript/flatten-a-list-2.js

@@ -0,0 +1,18 @@
+(function () {
+    'use strict';
+
+    // flatten :: Tree a -> [a]
+    function flatten(t) {
+        return (t instanceof Array ? concatMap(flatten, t) : t);
+    }
+
+    // concatMap :: (a -> [b]) -> [a] -> [b]
+    function concatMap(f, xs) {
+        return [].concat.apply([], xs.map(f));
+    }
+
+    return flatten(
+        [[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
+    );
+
+})();