It extracts the complete body portion owned by the stream of the incoming requests and exposes this extraction on the “req.body like something that is easier to interact with. This renders the user the middleware that uses the nodeJS or the zlib for unzipping the incoming data of request if it is zipped plus stream-utils or the raw-body in order to anticipate the full and raw contents belonging to the body of the request before "parsing it".

BY Best Interview Question ON 06 Jan 2020