Initial data commit

Task/24-game/JavaScript/24-game.js

@@ -0,0 +1,51 @@
+function twentyfour(numbers, input) {
+    var invalidChars = /[^\d\+\*\/\s-\(\)]/;
+
+    var validNums = function(str) {
+        // Create a duplicate of our input numbers, so that
+        // both lists will be sorted.
+        var mnums = numbers.slice();
+        mnums.sort();
+
+        // Sort after mapping to numbers, to make comparisons valid.
+        return str.replace(/[^\d\s]/g, " ")
+            .trim()
+            .split(/\s+/)
+            .map(function(n) { return parseInt(n, 10); })
+            .sort()
+            .every(function(v, i) { return v === mnums[i]; });
+    };
+
+    var validEval = function(input) {
+        try {
+            return eval(input);
+        } catch (e) {
+            return {error: e.toString()};
+        }
+    };
+
+    if (input.trim() === "") return "You must enter a value.";
+    if (input.match(invalidChars)) return "Invalid chars used, try again. Use only:\n + - * / ( )";
+    if (!validNums(input)) return "Wrong numbers used, try again.";
+    var calc = validEval(input);
+    if (typeof calc !== 'number') return "That is not a valid input; please try again.";
+    if (calc !== 24) return "Wrong answer: " + String(calc) + "; please try again.";
+    return input + " == 24.  Congratulations!";
+};
+
+// I/O below.
+
+while (true) {
+    var numbers = [1, 2, 3, 4].map(function() {
+        return Math.floor(Math.random() * 8 + 1);
+    });
+
+    var input = prompt(
+        "Your numbers are:\n" + numbers.join(" ") +
+        "\nEnter expression. (use only + - * / and parens).\n", +"'x' to exit.", "");
+
+    if (input === 'x') {
+        break;
+    }
+    alert(twentyfour(numbers, input));
+}