The **merkle-tree-stream** module provides a writable Node.js stream that incrementally builds a Merkle tree from incoming data chunks. Users supply custom leaf‑ and parent‑hash functions, and as data is written the stream emits objects describing each node (index, parent, hash, and original data), while exposing the current partial roots for continued tree construction. It’s aimed at developers who need a simple, stream‑based way to generate Merkle trees for verification, syncing, or content‑addressed storage.