How to Fix ReferenceError: document is not defined When Using ZEGOCLOUD API with Next.js

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Understanding the Problem

When you try to use the document object or any other browser-specific API during the server-side rendering process, you will encounter the error ReferenceError: document is not defined. This typically happens when you are trying to use the ZEGOCLOUD API, which relies on browser-specific mechanisms.

The Solution: Conditional Loading in useEffect

To prevent this error, the solution is to ensure that any code relying on the browser environment is only executed after the component has been mounted on the client side. One effective way to achieve this is by leveraging the useEffect hook in React to conditionally import the ZEGOCLOUD SDK.

Here’s how you can modify your existing code:

Step-by-Step Implementation

Import useEffect: Ensure you have imported the useEffect hook from React.

Conditional Import: Use the useEffect hook to dynamically import the ZEGOCLOUD library inside a client-side effect.

Here’s what your updated code would look like:

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

Explanation of the Code

useEffect Hook: The useEffect hook is executed after the component is fully mounted. This ensures that the code inside it will run only on the client side.

Dynamic Import: By using import("zego-express-engine-webrtc"), we ensure that the ZEGOCLOUD API is only accessed in a browser environment where the document object is available.

Promise Handling: The code utilizes promise handling to manage the SDK initialization. Once the ZEGOCLOUD SDK is successfully imported, you can proceed with your functionality seamlessly.

Conclusion