2016 Update

Task/Dot-product/JavaScript/dot-product-3.js

@@ -0,0 +1,21 @@
+(() => {
+    'use strict';
+
+    // dotProduct :: [Int] -> [Int] -> Int
+    const dotProduct = (xs, ys) => {
+        const sum = xs => xs ? xs.reduce((a, b) => a + b, 0) : undefined;
+
+        return xs.length === ys.length ? (
+            sum(zipWith((a, b) => a * b, xs, ys))
+        ) : undefined;
+    }
+
+    // zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
+    const zipWith = (f, xs, ys) => {
+        const ny = ys.length;
+        return (xs.length <= ny ? xs : xs.slice(0, ny))
+            .map((x, i) => f(x, ys[i]));
+    }
+
+    return dotProduct([1, 3, -5], [4, -2, -1]);
+})();

Task/Dot-product/JavaScript/dot-product-4.js

@@ -0,0 +1 @@
+3