In Express.js, how do you handle asynchronous errors within route handlers when not using `async/await`, and why is this handling critical?

When not using `async/await`, asynchronous errors in Express.js route handlers, typically arising from callback-based asynchronous functions (e.g., database queries or file system operations), must be explicitly caught and passed to the `next()` function. This is critical because uncaught errors within asynchronous operations will not be automatically caught by Express's default error handling middleware. This can lead to unhandled exceptions, causin....