Скачать или смотреть Solving the getStaticProps Serialization Error in Next.js with SWR

Learn how to resolve the `Error serializing` issue when using SWR with `getStaticProps` in Next.js. This guide simplifies the debugging process with explanations and code examples.
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This video is based on the question https://stackoverflow.com/q/66333610/ asked by the user 'c01d-br0th3r' ( https://stackoverflow.com/u/13715815/ ) and on the answer https://stackoverflow.com/a/66333682/ provided by the user 'Dmitry Minkovsky' ( https://stackoverflow.com/u/741970/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the getStaticProps Serialization Error in Next.js

When building applications using Next.js, developers often leverage the power of Static Site Generation (SSG) with the getStaticProps function. A common scenario arises when trying to use this feature alongside SWR, a popular library for data fetching. A frequent issue encountered is the error message indicating:

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

This post will delve into the causes of this serialization error and its effective solutions.

What Causes the Error?

The core of the issue lies in how getStaticProps sends data to the client. When this function is called, it attempts to serialize your JavaScript data into a JSON format, which can then be easily parsed on the client-side. However, JSON serialization comes with limitations:

Functions cannot be serialized as they are not a part of basic data types supported by JSON (like strings, numbers, Booleans, arrays, and objects).

If your data containing functions is returned from getStaticProps, the serialization process will fail, leading to the error you're encountering.

The Solution: Filtering Non-Serializable Data

To resolve this problem, you need to ensure that any data returned by your getStaticProps does not contain functions. This means filtering out any non-serializable properties before you return the data to the client.

Step-by-Step Guide to Fix the Error

Here’s how you can modify your getStaticProps function:

Identify Non-Serializable Properties: In your case, you need to look for properties in your data that could be functions. For example, suppose your fetched data has a property called myFunction.

Destructure the Data: Use JavaScript's destructuring assignment to separate non-serializable content from the rest of your data.

Return Clean Data: Ensure that you only return clean, serializable data from getStaticProps. Here’s how it can be implemented in code:

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

Explanation of the Code

Destructuring: In the above example, by using { myFunction, ...data }, we're effectively removing myFunction from the data object. The rest of the properties are preserved within the new data object.

Return Structure: Finally, the modified object containing only serializable values is returned as initialData, which can now be safely used by your SWR hook without throwing serialization errors.

Final Thoughts

Errors like "Error serializing" can be daunting but often stem from small oversights, such as returning non-serializable properties from getStaticProps. By ensuring your data is clean and conforms to JSON standards, you can circumvent these problems and make your Next.js application robust and user-friendly.

Don't let serialization issues deter you from harnessing the power of SWR alongside getStaticProps. With these steps in mind, you can solve the serialization error and effectively build your interface!