6-Use the .env File.txt

// (6) Use the .env File
// ex5 should be replaced with 6 from now
const mySecret = process.env['MESSAGE_STYLE']  // =uppercase (in your .env or Replit/Secrets)

app.get('/json', function(req, res){
  const msg = 'Hello json'
 process.env.MESSAGE_STYLE === 'uppercase' ?
    res.json({'message': msg.toUpperCase()}) :
    res.json({'message': msg})
})