Callback is a function passed as an argument to another function, allowing it to be invoked later, typically after an asynchronous operation completes. It's a way to continue execution after a concurrent operation finishes, which is why Node.js hipsters claim it's the key to their 10X productivity gains.

How to use it in a sentence

Did you hear about the callback hell John Doe ran into trying to impress his boss with his Node skills? He's still untangling that mess!

I told the PM I'd get back to her when the API callbacks complete, but I'm not holding my breath waiting for that 3rd party service to respond.

If you actually want to learn more...

• Martin Fowler dives into different data fetching patterns for single-page apps, including how to effectively use parallel requests with callbacks: Data Fetching Patterns in Single-Page Applications

• For a broader look at application architecture concepts like separating presentation and domain logic that can help manage callback complexity, check out Fowler's articles on the topic: Application Architecture

• If you're building microservices, understanding callbacks is key. This microservices guide covers topics like infrastructure as code and circuit breakers to help keep you out of callback trouble: Microservices Guide

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