Why is the React UseEffect Hook Running on Page Reload?

Discover why your React `UseEffect` hook is firing on every page reload and learn how to prevent it with a simple solution!
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Why is React UseEffect hook running on page reload

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Issue with React UseEffect

React's useEffect hook is a powerful tool that enables developers to perform side effects in function components. However, many new React users run into a common issue: the useEffect hook runs when the page is reloaded, even when it shouldn't. If you're experiencing this problem, you're not alone!

In this guide, we will explore why the useEffect hook executes each time you reload the page and, more importantly, how to fix it. We will break down the solution in manageable sections to ensure clarity.

What is Happening?

In React, useEffect runs after the render phase, and if its dependencies change, it executes again. However, when you reload the page, all components are rendered anew. This means that unless we specifically manage the execution of our useEffect, it will run by default.

In your case, you have the following useEffect:

[[See Video to Reveal this Text or Code Snippet]]

This code will log a message every time the page loads because the dependencies are reset during initialization, causing the useEffect to activate.

How to Fix It

The Solution: Using useRef

To prevent useEffect from executing on every page reload, you can leverage the useRef hook. Here’s the concept:

Initialize a Boolean Reference: Create a useRef that starts as true. This will act as a flag that indicates whether the component is running for the first time (on the initial page load).

Set and Check the Reference: In the useEffect, check if the useRef is true, and if so, set it to false. This prevents the code from running on the first render.

Run the Desired Code: Only after the initial render can you execute your desired side effects.

Code Implementation

Here’s how you can revise your current code:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Revised Code

const init = useRef(true);: This creates a mutable reference that persists throughout the component's lifetime, maintaining its value even after re-renders.

Conclusion

By understanding the behavior of the useEffect hook and employing a simple state management trick with useRef, you can control when your side effects are triggered, avoiding unwanted behavior on page reloads.

If you find your useEffect running more often than it should, remember to implement this strategy to manage your side effects effectively.

Happy coding, and may your React applications run smoothly!