Troubleshooting Hydration Failed Error in Next.js or react app

Introduction

Hydration is the process of taking a static HTML page and turning it into a dynamic React application. Next.js uses this process to render pages on the server and then sends the HTML to the client. The client-side JavaScript then takes over, and the page becomes interactive. This process is called client-side hydration.

Why hydration failed

The hydration failed error occurs when there is a mismatch between the server-rendered HTML and the client-side JavaScript. This can happen when the HTML and the JavaScript have different states, leading to inconsistencies and errors.

There are several reasons why hydration can fail in react app . One of the most common causes is when the server and client render different content. For example, if you have a component that fetches data from an API and the API response is different between the server and client, then the hydration process will fail.

Another reason for hydration failure is when the server and client render the same content but in different orders. For example, if the server renders a component before its dependencies, but the client renders the dependencies first, the hydration process will fail.

How to fix these problems

To fix the hydration failed error, you need to ensure that the server and client render the same content in the same order. One way to achieve this is by using data fetching methods provided by Next.js such as getStaticProps, getServerSideProps, or getInitialProps. These methods fetch data during the server rendering process, ensuring that the server and client render the same content.

Another way to fix the hydration failed error is by using the useEffect hook. The useEffect hook allows you to fetch data on the client-side after the component mounts, ensuring that the client and server render the same content.

import { useState, useEffect, useRef } from "react";

const Howitworks = () => {
  const [initialRenderComplete, setInitialRenderComplete] = useState(false);
  // This useEffect will only run once, during the first render
  useEffect(() => {
    // Updating a state causes a re-render
    setInitialRenderComplete(true);
  }, []);

  return <>{initialRenderComplete ? <>hi write here code</> : null}</>;
};
export default Howitworks;

In conclusion, the hydration failed error is a common error that can occur while working with Next.js. To fix this error, you need to ensure that the server and client render the same content in the same order. This can be achieved by using data fetching methods provided by Next.js or by using the useEffect hook to fetch data on the client-side. By following these steps, you can ensure that your Next.js application runs smoothly and without errors.