2016 Update

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([[]])
+    }
+
+})();

Task/Power-set/JavaScript/power-set-3.js

@@ -0,0 +1,5 @@
+{
+ "[1,2,3] ->":[[], [3], [2], [2, 3], [1], [1, 3], [1, 2], [1, 2, 3]],
+ "empty set ->":[[]],
+ "set which contains only the empty set ->":[[], [[]]]
+}

Task/Power-set/JavaScript/power-set-4.js

@@ -0,0 +1,19 @@
+(() => {
+    'use strict';
+
+    // powerset :: [a] -> [[a]]
+    const powerset = xs =>
+        xs.reduceRight((a, x) => a.concat(a.map(y => [x].concat(y))), [
+            []
+        ]);
+
+
+    // TEST
+    return {
+        '[1,2,3] ->': powerset([1, 2, 3]),
+        'empty set ->': powerset([]),
+        'set which contains only the empty set ->': powerset([
+            []
+        ])
+    };
+})()

Task/Power-set/JavaScript/power-set-5.js

@@ -0,0 +1,3 @@
+{"[1,2,3] ->":[[], [3], [2], [2, 3], [1], [1, 3], [1, 2], [1, 2, 3]],
+"empty set ->":[[]],
+"set which contains only the empty set ->":[[], [[]]]}