Middleware functions are the backbone of modern web frameworks. They allow you to plug in logic (logging, auth, error handling) that wraps around your core business logic.

The Onion Model: Each middleware has a "downstream" phase (before next()) and an "upstream" phase (after await next()).

Downstream: Executed in the order the middlewares were registered.
The Core: The final middleware or the end of the chain.
Upstream: Executed in reverse order as the promises resolve and control flows back up the stack.

Requirements:

Accepts any number of middleware functions.
Returns a single function that takes a context object.
Returns a Promise that resolves only when the entire chain is finished.
The next() function must trigger the next middleware and return a Promise.

💡 Examples

const logger = async (ctx, next) => {
  console.log('Start');
  await next();
  console.log('End');
};

const businessLogic = async (ctx, next) => {
  ctx.data = "Processed";
  await next();
};

const composed = middlewares(logger, businessLogic);
await composed({}); 
// Output: 
// "Start"
// "End"