Initial data commit

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

@@ -0,0 +1,46 @@
+(() => {
+    "use strict";
+
+    // ------------------- DOT PRODUCT -------------------
+
+    // dotProduct :: [Num] -> [Num] -> Either Null Num
+    const dotProduct = xs =>
+        ys => xs.length === ys.length
+            ? sum(zipWith(mul)(xs)(ys))
+            : null;
+
+
+    // ---------------------- TEST -----------------------
+
+    // main :: IO ()
+    const main = () =>
+        dotProduct([1, 3, -5])([4, -2, -1]);
+
+
+    // --------------------- GENERIC ---------------------
+
+    // mul :: Num -> Num -> Num
+    const mul = x =>
+        y => x * y;
+
+
+    // sum :: [Num] -> Num
+    const sum = xs =>
+    // The numeric sum of all values in xs.
+        xs.reduce((a, x) => a + x, 0);
+
+
+    // zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
+    const zipWith = f =>
+    // A list constructed by zipping with a
+    // custom function, rather than with the
+    // default tuple constructor.
+        xs => ys => xs.map(
+            (x, i) => f(x)(ys[i])
+        ).slice(
+            0, Math.min(xs.length, ys.length)
+        );
+
+    // MAIN ---
+    return main();
+})();