JWT

browser.js

function work() {
  console.log('Working');
  setTimeout(work, 0);
}

work();
// This won't halt the MAIN JS THREAD!
// Because we keep adding to the JOB queue


// However, this will:
function halt() {
   while(true) {}
}

setTimeout(halt, 2000)

express.js

import express from 'express'
import jwt from 'jsonwebtoken'
import fs from 'fs'

const app = express();

app.use(express.json());

function msg(msg) {
  return {msg};
}

app.get('/', (req, resp) => {
  resp.send(msg('Welcome to my order server!'));
})

app.post('/login', (req, resp) => {
  fs.readFile('./users.json', {encoding: 'utf-8'}, (err, data) => {
    if(err) {
      resp.status(503);
      resp.send(msg('Service is not avialable'));
      return;
    }

    const {email} = req.body;
    const users = JSON.parse(data);
    const user = users.find(user => user.email === email);
    if (user) {
      jwt.sign({id: user.id}, 'secret', {expiresIn: 60}, (err, token) => {
        if (err) {
          resp.status(403);
          resp.send(msg('Not Authorized'));
          return;
        }

        resp.send({token});
      });
    } else {
      resp.status(403);
      resp.send(msg('Not Authorized'));
    }
  })
});

app.get('/orders', (req, resp) => {
  const authHeader = req.headers['authorization'];
  const token = authHeader.split(' ')[1];

  jwt.verify(token, 'secret', (err, token_data) => {
    if (err) {
      resp.status(403);
      resp.send(msg('Not Authorized'));
      return;
    }

    fs.readFile('./orders.json', {encoding: 'utf-8'}, (err, data) => {
      if(err) {
        resp.status(503);
        resp.send('Service is not avialable');
        return;
      }
  
      resp.send({orders: JSON.parse(data), operator_id: token_data.id})
    })
  })

  
})

app.listen(3333, () => {
  console.log('Listening at http://localhost:3333')
})