2016 Update

Task/Catamorphism/JavaScript/catamorphism-2.js

@@ -0,0 +1,21 @@
+(function (xs) {
+    'use strict';
+
+    // foldl :: (b -> a -> b) -> b -> [a] -> b
+    function foldl(f, acc, xs) {
+        return xs.reduce(f, acc);
+    }
+
+    // foldr :: (b -> a -> b) -> b -> [a] -> b
+    function foldr(f, acc, xs) {
+        return xs.reduceRight(f, acc);
+    }
+
+    // Test folds in both directions
+    return [foldl, foldr].map(function (f) {
+        return f(function (acc, x) {
+            return acc + (x * 2).toString() + ' ';
+        }, [], xs);
+    });
+
+})([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);

Task/Catamorphism/JavaScript/catamorphism-3.js

@@ -0,0 +1,5 @@
+var nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+console.log(nums.reduce((a, b) => a + b, 0)); // sum of 1..10
+console.log(nums.reduce((a, b) => a * b, 1)); // product of 1..10
+console.log(nums.reduce((a, b) => a + b, '')); // concatenation of 1..10