Initial data commit

Task/Power-set/JavaScript/power-set-2.js

@@ -0,0 +1,21 @@
+(function () {
+
+   // translating:  powerset = foldr (\x acc -> acc ++ map (x:) acc) [[]]
+
+    function powerset(xs) {
+        return xs.reduceRight(function (a, x) {
+            return a.concat(a.map(function (y) {
+                return [x].concat(y);
+            }));
+        }, [[]]);
+    }
+
+
+    // TEST
+    return {
+        '[1,2,3] ->': powerset([1, 2, 3]),
+        'empty set ->': powerset([]),
+        'set which contains only the empty set ->': powerset([[]])
+    }
+
+})();