JavaScript beyond the webpage
JavaScript can make a webpage respond to clicks. Node.js and Deno also run JavaScript where there is no webpage, such as on a server or in a command-line tool. They are runtimes: they provide the environment the code needs while it runs.
A team might use one to serve an API, process a file, or run build tools. Both can use reusable packages, but they differ in their built-in tools, permissions, and package conventions. They are alternatives for some tasks, not programming languages themselves.