Express API without best practices :v - Sprotify

index.js

const mysql = require('mysql')
const express = require('express')

const app = express()

app.use(express.json())
app.use(express.urlencoded({ extended: false }))

// Connection database
const connection = mysql.createConnection({
  host: '127.0.0.1',
  user: 'root',
  password: 'root',
  database: 'mydb'
})


// Routing
const router = express.Router();

// GET /
router.get('/', (req, res) => {
  return res.json({
    message: mensaje
  })
})

connection.connect()

router.get('/artist', (req, res) => {
  const whereCondition = (req.query.id) ? ` WHERE idartistas = ${req.query.id}` : ''
  connection.query(`SELECT * FROM artistas ${whereCondition}`, (err, results, fields) => {
    if (err) return res.json({ error: err })
    return res.json({ data: results })
  })
})

router.post('/artist', (req, res) => {
  console.log(req)
  connection.query(`
  INSERT INTO artistas(nombre, debut, valoracion, bio)
  VALUES(
    "${req.body.nombre}", 
    "${req.body.debut}",
    ${req.body.valoracion},
    "${req.body.bio}"
  )
  `, (err, results, fields) => {
    if (err) return res.json({ error: err })
    return res.json({
      message: 'Artist created!'
    });
  })
});

app.use('/', router);
app.listen('8080');
console.log('Listening on port 8080')