Fix React useEffect Infinite Loops with useDeepCompareEffect

What you’ll get

You will learn how to use useDeepCompareEffect to replace the standard useEffect hook in your React applications. This prevents infinite loops caused by object dependencies changing their value on every render, ensuring your effects run only when truly necessary.

This approach works because useDeepCompareEffect performs a deep comparison of its dependencies, checking their contents rather than just their memory addresses.

Tools you need

• React (free): A JavaScript library for building user interfaces.
• @reactuses/core (free): A collection of custom React Hooks, including useDeepCompareEffect.

Steps

1. Install the library: Open your project’s terminal and install the @reactuses/core package.

   npm install @reactuses/core
   # or
   yarn add @reactuses/core

   You should see the package added to your project’s dependencies.

2. Import useDeepCompareEffect: In your React component file, import useDeepCompareEffect alongside the standard useEffect.

   import { useEffect as useDeepCompareEffect } from '@reactuses/core';
   import React, { useState, useEffect } from 'react';

   You will now have useDeepCompareEffect available for use.

3. Replace useEffect with useDeepCompareEffect: Find the useEffect hook in your component that is causing an infinite loop due to an object in its dependency array. Replace useEffect with useDeepCompareEffect.

   Original code (causing infinite loop):

   function Results ({ term , page }) {
     const [ rows , setRows ] = useState ([]);
     const query = { term , page , sort : ' desc ' }; // new object, every render
   
     useEffect (() => {
       fetchRows ( query ). then ( setRows );
     }, [ query ]); // 'query' is a new object on every render
   }

   Modified code using useDeepCompareEffect:

   function Results ({ term , page }) {
     const [ rows , setRows ] = useState ([]);
     const query = { term , page , sort : ' desc ' };
   
     useDeepCompareEffect (() => {
       fetchRows ( query ). then ( setRows );
     }, [ query ]); // 'query' is now deep-compared
   }

   The effect will now only re-run if the term, page, or sort properties within the query object actually change their values, not just because a new object is created.

Original source

This workflow is based on a blog post by childrentime, shared on DEV Community. It explains how React’s default useEffect hook compares object dependencies by reference, leading to infinite loops, and offers useDeepCompareEffect as a solution.

Notes & variations

• Common mistake: Forgetting to import useDeepCompareEffect or incorrectly replacing useEffect can lead to the same infinite loop issue. Ensure you are using the imported hook correctly.
• Tip for better results: While useDeepCompareEffect solves the dependency comparison problem, consider if the query object itself can be memoized using useMemo if it’s derived from other state or props. This can sometimes offer performance benefits by preventing the query object from being recreated unnecessarily in the first place.
• Free tier viability: Both React and @reactuses/core are free to use, making this solution accessible without cost.