Implement merge method for merge sort

Author: KarenOk

Sorting/MergeSort.js

@@ -0,0 +1,22 @@
+function merge(arr1, arr2, comparator) {
+if (typeof comparator !== "function") {
+comparator = (a, b) => a - b;
+}
+
+const result = [];
+let p1 = 0,
+p2 = 0;
+
+while (p1 < arr1.length && p2 < arr2.length) {
+if (comparator(arr1[p1], arr2[p2]) < 0) {
+result.push(arr1[p1]);
+p1++;
+} else {
+result.push(arr2[p2]);
+p2++;
+}
+}
+return result.concat(arr1.slice(p1), arr2.slice(p2));
+}
+
+merge([1, 3, 6, 7], [2, 4, 6]);