Parent's code with callbacks would be more like this:

  fetch((err, res) => {
    if (err) {
      // yay - error handling! :)
    }

    res.json((err, myJson) => {
      if (err) {
        // oh no - another error handler :(
      }
      
      // do stuff
    });
  }

fetch.json is async as well. With await the try / catch would just be around both await calls.