Breadth-first search (BFS) is an algorithm used to traverse or search through graph structures, typically implemented using a queue. BFS starts at a specified node (or root in the case of a tree) and explores all its neighbors at the present depth before moving on to nodes at the next level of depth. In TypeScript, you can implement BFS by using a queue data structure to manage the nodes to be visited. Starting from the initial node, you enqueue its neighbors and continue processing nodes until there are no more nodes left. BFS is particularly useful for finding the shortest path in unweighted graphs and is applied in scenarios like network broadcasting, finding connected components, and AI pathfinding (like in maze-solving problems). The BFS implementation in TypeScript requires handling an adjacency list to represent the graph, a visited set to avoid processing the same node multiple times, and a queue for the iterative exploration of nodes. BFS can be used in various domains such as social networks (for finding connections), AI (for solving puzzles), or even web crawling (for processing a breadth-first search across links).