update: new problem added

Author: ashokdey

src/_Problems_/compose-largest-number/compose-largest.test.js

@@ -0,0 +1,35 @@
+/** Given an array of numbers, return the highest number that can be made out of it */
+
+/**
+ * Test cases
+ * [3, 6, 0, 9] -> 9630
+ * [60, 548] -> 60548
+ * [1, 34, 3, 98, 9, 76, 45, 4] -> 998764543431
+ */
+
+/** At first glance, the below solution may seem the answer */
+const hightestNumber = Number([60, 548].sort((a, b) => b - a).join(""));
+
+/** The above will fail for test case 2 & 3 */
+
+/** We need a custom compare funtion */
+function compare(a, b) {
+  const x = Number(String(a) + String(b));
+  const y = Number(String(b) + String(a));
+  return x > y ? -1 : 1;
+}
+
+/** final function */
+function composeHighest(arr) {
+  if (!arr || !Array.isArray(arr)) {
+    throw new Error("Invalid array/missing argument");
+  }
+
+  return Number(arr.sort(compare).join(""));
+}
+
+/** tests */
+
+console.log(composeHighest([3, 6, 0, 9]) === 9630);
+console.log(composeHighest([60, 548]) === 60548);
+console.log(composeHighest([1, 34, 3, 98, 9, 76, 45, 4]) === 998764543431);