Initial data commit

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-1.js

@@ -0,0 +1,8 @@
+var a = ["a","b","c"],
+    b = ["A","B","C"],
+    c = [1,2,3],
+    output = "",
+    i;
+for (i = 0; i < a.length; i += 1) {
+    output += a[i] + b[i] + c[i] + "\n";
+}

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-2.js

@@ -0,0 +1,14 @@
+var lstOut = ['', '', ''];
+
+[["a", "b", "c"], ["A", "B", "C"], ["1", "2", "3"]].forEach(
+  function (a) {
+    [0, 1, 2].forEach(
+      function (i) {
+        // side-effect on an array outside the function
+        lstOut[i] += a[i];
+      }
+    );
+  }
+);
+
+// lstOut --> ["aA1", "bB2", "cC3"]

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-3.js

@@ -0,0 +1,17 @@
+(function (lstArrays) {
+
+    return lstArrays.reduce(
+        function (a, e) {
+            return [
+                a[0] + e[0],
+                a[1] + e[1],
+                a[2] + e[2]
+            ];
+        }, ['', '', ''] // initial copy of the accumulator
+    ).join('\n');
+
+})([
+    ["a", "b", "c"],
+    ["A", "B", "C"],
+    ["1", "2", "3"]
+]);

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-4.js

@@ -0,0 +1,16 @@
+(function (x, y, z) {
+
+    // function of arity 3 mapped over nth items of each of 3 lists
+    // (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
+    function zipWith3(f, xs, ys, zs) {
+        return zs.length ? [f(xs[0], ys[0], zs[0])].concat(
+            zipWith3(f, xs.slice(1), ys.slice(1), zs.slice(1))) : [];
+    }
+
+    function concat(x, y, z) {
+        return ''.concat(x, y, z);
+    }
+
+    return zipWith3(concat, x, y, z).join('\n')
+
+})(["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]);

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-5.js

@@ -0,0 +1,25 @@
+(function () {
+    'use strict';
+
+    // zipListsWith :: ([a] -> b) -> [[a]] -> [[b]]
+    function zipListsWith(f, xss) {
+        return (xss.length ? xss[0] : [])
+            .map(function (_, i) {
+                return f(xss.map(function (xs) {
+                    return xs[i];
+                }));
+            });
+    }
+
+    // concat :: [a] -> s
+    function concat(lst) {
+        return ''.concat.apply('', lst);
+    }
+
+    // TEST
+    return zipListsWith(
+        concat,
+        [["a", "b", "c"], ["A", "B", "C"], [1, 2, 3]]
+    )
+    .join('\n');
+})();

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-6.js

@@ -0,0 +1,3 @@
+aA1
+bB2
+cC3

Task/Loop-over-multiple-arrays-simultaneously/JavaScript/loop-over-multiple-arrays-simultaneously-7.js

@@ -0,0 +1,33 @@
+(() => {
+    'use strict';
+
+    // GENERIC FUNCTIONS -----------------------------------------------------
+
+    // concat :: [[a]] -> [a]
+    const concat = xs =>
+        xs.length > 0 ? (() => {
+            const unit = typeof xs[0] === 'string' ? '' : [];
+            return unit.concat.apply(unit, xs);
+        })() : [];
+
+    // map :: (a -> b) -> [a] -> [b]
+    const map = (f, xs) => xs.map(f);
+
+    // transpose :: [[a]] -> [[a]]
+    const transpose = xs =>
+        xs[0].map((_, col) => xs.map(row => row[col]));
+
+    // unlines :: [String] -> String
+    const unlines = xs => xs.join('\n');
+
+    // TEST ------------------------------------------------------------------
+    const xs = [
+        ['a', 'b', 'c'],
+        ['A', 'B', 'C'],
+        [1, 2, 3]
+    ];
+
+    return unlines(
+        map(concat, transpose(xs))
+    );
+})();