A dramatic dialogue about async evolution in JavaScript:

The Callback Era

function read(filename, callback) {
  fs.readFile(filename, 'utf8', function(err, res) {
    if (err) return callback(err);
    callback(null, res);
  });
}

Avoiding Callback Hell:

• Name your functions
• Keep code shallow
• Modularize
• Bind this

The Promise Era

promise.then(result => {
  console.log(result);
}).catch(err => {
  console.log(err);
});

## The Async/Await Era
javascript
async function getData() {
  const result = await fetch(url);
  return result.json();
}

From callbacks to Promises to async/await - the journey continues!