Question

What is an error-first callback in Node.js?

Answer 1

If Google’s V8 Engine is the heart of your Node.js application, then callbacks are its veins. They enable a balanced, non-blocking flow of asynchronous control across modules and applications. But for callbacks to work at scale you’ll needed a common, reliable protocol. The “error-first” callback (also known as an “errorback”, “errback”, or “node-style callback”) was introduced to solve this problem, and has since become the standard for Node.js callbacks. This post will define this pattern, its best practices, and exactly what makes it so powerful.