The npm compression package is a middleware that can compress response bodies for requests that traverse through it. This helps reduce the size of data that's sent over the network, leading to quicker response times and lower bandwidth usage. It uses the zlib library to perform gzip or deflate compression, both of which are widely supported by modern web browsers.
Cookies are small pieces of data that a website sends to a user's web browser while the user is browsing that website. Every time the user loads the website, the browser sends the cookie back to the server to notify the website of the user's previous activity.