Simple express server

index.js

import express from 'express';
import { 
  simpleCalculation, 
  complexCalculation
} from './utils'

// Set up app
const app = express();
const port = process.env.PORT ?? 8080;

// Set up routes
const router = express.Router();

router.get('/api/simple', (req, res) => {
  const result = simpleCalculation();
  res.json(result);
});
router.get('/api/complex', (req, res) => {
  const result = complexCalculation();
  res.json(result);
});

app.use('/', router);

// Start server
const server = app.listen(port, () => {
  console.log(`Server listening on port ${port}`);
});