2016 Update

Task/Factorial/JavaScript/factorial-4.js

@@ -1 +1,27 @@
-var factorial = n => (n < 2) ? 1 : n * factorial(n - 1);
+(function () {
+    'use strict';
+
+    // factorial :: Int -> Int
+    function factorial(x) {
+
+        return range(1, x)
+            .reduce(function (a, b) {
+                return a * b;
+            }, 1);
+    }
+
+
+
+    // range :: Int -> Int -> [Int]
+    function range(m, n) {
+        var a = Array(n - m + 1),
+            i = n + 1;
+
+        while (i-- > m) a[i - m] = i;
+        return a;
+    }
+
+
+    return factorial(18);
+
+})();

Task/Factorial/JavaScript/factorial-5.js

@@ -0,0 +1 @@
+6402373705728000

Task/Factorial/JavaScript/factorial-6.js

@@ -0,0 +1 @@
+var factorial = n => (n < 2) ? 1 : n * factorial(n - 1);

Task/Factorial/JavaScript/factorial-7.js

@@ -0,0 +1,20 @@
+(function (n) {
+    'use strict';
+
+    // factorial :: Int -> Int
+    let factorial = (n) => range(1, n).reduce(product, 1);
+
+
+    // product :: Num -> Num -> Num
+    let product = (a, b) => a * b,
+
+        // range :: Int -> Int -> [Int]
+        range = (m, n) =>
+            Array.from({
+                length: (n - m) + 1
+            }, (_, i) => m + i)
+
+
+    return factorial(n);
+
+})(18);