test.js

const compose = require('koa-compose');
const sleep = require('sleep-promise');

/**
 * Simple App Structure.
 */
class App {

  constructor () {
    this.middleware = [];
  }

  use (fn) {
    if (typeof fn !== 'function') {
      throw new TypeError('middleware must be a function!');
    }

    this.middleware.push(fn);

    return this;
  }

  route (handler) {
    let fn = compose(this.middleware);
    return fn(this).then( () => this.handleRequest(handler) );
  }

  handleRequest (handler) {
    return handler();
  }
}

let app = new App();

/**
 * Setup Middleware
 */
app.use( (ctx, next) => {
  console.log("Middleware #1: Triggered");
  console.log("Middleware #1: Next");
  return next();
});

app.use( (ctx, next) => {
  console.log("Middleware #2: Triggered");
  console.log("Middleware #2: Next");
  return next();
});

app.use( (ctx, next) => {
  console.log("Middleware #3: Triggered");
  return sleep(2000).then( () => {
    console.log("Middleware #3: Next");
    return next();
  });
});

app.route(() => console.log("Finished") );