1-id.js

'use strict';

const http = require('node:http');
const { AsyncLocalStorage } = require('node:async_hooks');

const application = {
  nextRequestId: 0,
  asyncLocalStorage: new AsyncLocalStorage(),
  user: { name: 'Marcus', balance: 0 },
};

const routing = {
  '/': '<h1>welcome to homepage</h1><hr>',
  '/user': application.user,
  '/user/name': () => application.user.name.toUpperCase(),
  '/user/balance': () => application.user.balance,
  '/api/method1': async (req, res) => {
    const id = application.asyncLocalStorage.getStore();
    console.log(`${id} ${req.method} ${req.url} ${res.statusCode}`);
    application.asyncLocalStorage.exit(() => {
      if (id) console.log({ id });
    });
    return { id, user: application.user };
  },
};

const types = {
  object: JSON.stringify,
  string: (s) => s,
  undefined: () => 'not found',
  function: async (fn, req, res) => {
    const result = await fn(req, res);
    return JSON.stringify(result);
  },
};

http.createServer((req, res) => {
  const data = routing[req.url];
  const type = typeof data;
  const endpoint = types[type];
  const id = application.nextRequestId++;
  application.asyncLocalStorage.run(id, async () => {
    const result = await endpoint(data, req, res);
    res.end(result);
  });
}).listen(8000);

setInterval(() => {
  application.user.balance += 10;
}, 1000);