Understanding the undefined Issue When Fetching Data from GraphQL in Next.js

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The Problem: Getting undefined in Your GraphQL Queries

Your Scenario

You have a GraphQL API endpoint:

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

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

The Problematic Code

When you try to log the categories:

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

you get undefined. This happens because the getStaticProps function does not get executed in the scope of the Hero component itself.

The Solution: Correctly Passing Data with getStaticProps

Here’s How to Fix It:

Move the Data Fetching Logic: Define getStaticProps in the page component that renders the Hero component.

Pass Props: Pass the fetched categories as props to the Hero component.

Here’s what the revised code might look like:

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

Key Changes Explained

Page Component: The Home function is now the page component, which utilizes getStaticProps.

Proper Data Flow: By passing categories as a prop to Hero, you ensure that it has access to the data fetched by getStaticProps.

Conclusion

Troubleshooting Tips

Always confirm that getStaticProps is in the page component.

Ensure your API endpoint is correct and responsive.