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Callback functions are integral to the way JavaScript handles asynchronous logic like API calls, event handling, etc. But callbacks can get messy pretty quickly without some solid fundamentals.
In this tutorial, we’ll provide a proper introduction to callbacks in JS — what they are, why they’re useful, and most importantly, best practices to avoid messy “callback hells”.
We’ll cover topics like:
- The basics: passing functions as arguments
- Classic examples of callbacks
- Common issues like nesting
- Better ways to handle async logic
By the end, you’ll have an solid understanding of callbacks and some good rules of thumb to leverage them effectively.
Let’s dive in!
What are JavaScript Callbacks?
In JavaScript, functions are first-class citizens. We can pass them as arguments to other functions and call them dynamically throughout our code. Functions that get passed like this are called callback functions.
