“Fixing Hydration Issues in Next.js and Zustand: A Simple Solution”

As web developers, we often face the issue of hydration when working with frameworks such as Next.js and state management tools like Zustand. Hydration refers to the process of rendering the HTML page and loading the JavaScript bundle in the browser, and it is crucial for the proper functioning of our web application. In this blog post, we’ll look at how to fix hydration issues in Next.js and Zustand.

Introduction

When we use Next.js with Zustand, we can face hydration issues. This happens because the server renders the HTML with some initial state, and then the client-side JavaScript takes over and initialises the Zustand store. If the initial state is different from the state that the client-side JavaScript initializes, it can cause inconsistencies in our application.

The solution

To fix this issue, we can create a simple component that waits for the Next.js hydration to complete before rendering our application. We can call this component HydrationZustand. Here's the code:

import { useEffect, useState } from "react"

const HydrationZustand = ({ children }) => {
  const [isHydrated, setIsHydrated] = useState(false)

  // Wait till Next.js rehydration completes
  useEffect(() => {
    setIsHydrated(true)
  }, [])

  return <>{isHydrated ? <div>{children}</div> : null}</>
}

export default HydrationZustand

This component waits for the Next.js rehydration to complete by using the useEffect hook. Once the rehydration is complete, it sets the isHydrated state to true, which allows the children to be rendered.

Next, we need to wrap our application with the HydrationZustand component. We can do this in our _app.js file. Here's the code:

import "../scss/style.default.scss
import Layout from "../components/Layout"
import HydrationZustand from "./hydrationZustand"

function App({ Component, pageProps }) {
  return (
    <HydrationZustand>
      <Layout {...pageProps}>
        <Component {...pageProps} />
      </Layout>
    </HydrationZustand>
  )
}

export default App

Here, we’re wrapping our Layout component with HydrationZustand. This ensures that our application is only rendered once the hydration is complete. Any state management tool, including Zustand, will work properly with this approach.

Examples

1. Inconsistent UI: If the initial state of the application on the server side and the client side is different, it can cause UI bugs or inconsistencies. For example, a button may appear as enabled on the server side, but when the client-side JavaScript takes over, it may be disabled because of a different state.
2. Broken functionality: In some cases, hydration issues can cause the application to crash or break functionality. For instance, if the server-side rendering and client-side rendering are inconsistent, it can lead to errors such as “undefined is not a function” or “cannot read property of null”.
3. Performance issues: Hydration issues can also lead to performance problems. For example, if the server-side rendering and client-side rendering are inconsistent, the browser may need to render the same components multiple times, leading to unnecessary re-renders and slower page load times.

By understanding these examples, developers can see how important it is to properly manage hydration in their Next.js and Zustand applications.

Conclusion

In conclusion, fixing hydration issues in Next.js and Zustand is essential for the proper functioning of our web applications. By using the HydrationZustand component, we can ensure that our application is rendered only after the Next.js rehydration is complete. This simple fix can save us from a lot of headaches and inconsistencies in our application.

References

• Next.js documentation: https://nextjs.org/docs/
• Zustand documentation: https://docs.pmnd.rs/zustand