Merge sort is a classic divide-and-conquer sorting algorithm that works by recursively dividing an array into smaller subarrays, sorting them, and then merging them back together in sorted order. In TypeScript, merge sort can be implemented by writing a recursive function that splits the array in half, sorts each half recursively, and merges the sorted halves. The merge step is the key part of the algorithm, where two sorted subarrays are combined into one sorted array. Merge sort has a time complexity of O(n log n), making it highly efficient for large datasets. Unlike quicksort, merge sort guarantees this time complexity even in the worst case. However, merge sort is not an in-place sorting algorithm and requires additional memory for the merging process. It is commonly used in applications where stability (preserving the order of equal elements) is important, such as in external sorting (sorting large datasets stored on disk) or in situations where memory usage is not a constraint. Learning merge sort in TypeScript gives you a strong foundation in recursive algorithms and efficient sorting techniques.