Callback hell

https://www.freecodecamp.org/news/how-to-deal-with-nested-callbacks-and-avoid-callback-hell-1bc8dc4a2012/

// Makes a burger
// makeBurger contains four steps:
//   1. Get beef
//   2. Cook the beef
//   3. Get buns for the burger
//   4. Put the cooked beef between the buns
//   5. Serve the burger (from the callback)
// We use callbacks here because each step is asynchronous.
//   We have to wait for the helper to complete the one step
//   before we can start the next step

const makeBurger = nextStep => {
  getBeef(function(beef) {
    cookBeef(beef, function(cookedBeef) {
      getBuns(function(buns) {
        putBeefBetweenBuns(buns, beef, function(burger) {
          nextStep(burger);
        });
      });
    });
  });
};