16 What is the SFRA 'server' module and what methods does it expose?

The server module is the central SFRA framework object imported at the top of every controller file:

var server = require('server');

It exposes the following key methods:

1. Route registration — server.get(name, ...middleware), server.post(name, ...middleware), server.use(name, ...middleware) for any HTTP method
2. Route inheritance — server.extend(require('controllers/TargetController')) imports all routes from another controller into the current one, enabling extension
3. Route modification — server.append(name, ...middleware), server.prepend(name, ...middleware), server.replace(name, ...middleware) modify inherited routes
4. Exports — module.exports = server.exports() at the end of every controller file exposes registered routes to the B2C Commerce router

Each middleware function in a route receives (req, res, next) — call next() to advance, next(true) to stop the chain and render the current response.