Скачать или смотреть Understanding relayStylePagination: Why Your Apollo Queries Aren't Refetching on Variable Changes

Discover why using `relayStylePagination` in Apollo Client can prevent queries from refetching when variables change, and learn how to properly handle variable updates.
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Understanding relayStylePagination: Why Your Apollo Queries Aren't Refetching on Variable Changes

When developing applications with Apollo Client, you might encounter an issue where changing the variables passed to a query does not trigger a refetch, even when calling the refetch function manually. This can be particularly frustrating, especially when using the relayStylePagination helper function. In this post, we'll explore this issue and provide a solution to ensure your queries are dynamically fetching the latest data as intended.

The Core Issue

The Problem

As mentioned, when you apply the relayStylePagination in your Apollo Client cache type policies, modifications to the variables within a query don't automatically trigger a refetch. Instead, it continues to return the cached data unless explicitly told to do otherwise.

Here's a quick recap of the scenario:

You have a query set up to fetch data based on certain variables.

You utilize relayStylePagination to manage paginated data.

Upon changing those query variables, the expected behavior of automatically refetching does not occur.

Why Does This Happen?

The root of this problem lies in how the relayStylePagination function works with Apollo's caching mechanism. When this pagination strategy is in effect, it revolves mostly around merging new data rather than always refetching data based on variable changes. This means that while subsequent calls fetch more data correctly using fetchMore, the initial data fetching based on variable changes does not automatically occur.

Solution: Manually Refetching with Updated Variables

Implementing a Manual Refetch

To address this issue, you can manually trigger a refetch with the new variables. This approach is straightforward and effective when dealing with the current limitations of the relayStylePagination method.

How to Manually Refetch

Call the refetch Method: When you need to update the query based on new variables, you can explicitly call the refetch function associated with your query.

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Ensure Updated Variables: Pass in the updated variables to the refetch call to ensure the query retrieves the latest results based on those changes.

Things to Remember

Cached Data: The relayStylePagination is designed to optimize data fetching by caching and merging new queries instead of always reaching out for fresh data.

Manual Overrides: Whenever automatic refetching isn’t working as expected, employing manual refetches is a reliable workaround.

Stay Updated: Consider checking Apollo Client documentation and community resources for updates on caching behavior that may improve or change how pagination and refetching work in future releases.

Conclusion

In conclusion, while using relayStylePagination with Apollo Client can present some challenges in terms of query refetching under variable changes, a simple workaround exists in manually invoking a refetch. By following the techniques outlined in this guide, you can ensure that your application retrieves and displays accurate and up-to-date data every time your input variables change.

Remember, effective data management is crucial to providing a seamless user experience, and understanding your caching strategy is a key element in that process.

Keep experimenting, and happy coding!