Q5: What is an error-first callback in Node.js?
An error-first callback passes an error object as its first parameter. If no error occurred, the first parameter is null or undefined.
Key Takeaways
- First argument is reserved for errors:
(err, result) => {}. - Standard convention in traditional asynchronous Node.js APIs.
Knowledge Check
In error-first callbacks, what is the value of the error parameter when execution succeeds?