TANSTACK ROUTER SERVER FUNCTIONS

Summary from the TLDR Web Dev newsletter

TanStack Router's Server Functions allows developers to execute code only on the server, keeping sensitive logic away from the client. They are defined using `createServerFn` and can be called from anywhere in the application, including loaders, hooks, and other server functions. Server functions accept a single parameter and also provide access to server request context, allowing developers to work with headers, sessions, and cookies.