# Introduction In this lab, we will be exploring the concept of finding the last insertion index in a sorted array. We will learn how to check if the array is sorted in descending order and how to use `Array.prototype.reverse()` and `Array.prototype.findIndex()` to find the appropriate last index where the element should be inserted. By the end of this lab, you will have a better understanding of how to maintain the sort order of an array.
Click the virtual machine below to start practicing