Solving the undefined Response Issue with RTK Query in React

Описание: Learn how to effectively troubleshoot and resolve the issue of getting `undefined` data from RTK Query GET requests in your React application.
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This video is based on the question https://stackoverflow.com/q/75579754/ asked by the user 'randeepsarma24' ( https://stackoverflow.com/u/14120802/ ) and on the answer https://stackoverflow.com/a/77230586/ provided by the user 'Diego Longo' ( https://stackoverflow.com/u/15776532/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting RTK Query GET Request Returning undefined

If you've ever faced issues while trying to retrieve data using RTK Query in a React application, you're not alone. Many developers encounter situations where their GET request returns undefined, leaving them puzzled about what went wrong. In this post, we'll explore a common scenario where this can happen and how to effectively troubleshoot and resolve it.

Understanding the Problem

In your setup, you are utilizing RTK Query to fetch user data based on a token, but the API call is returning an unexpected result. Instead of the expected user data, your console shows an object indicating the status is pending, and isSuccess is false. This can be frustrating, especially when the backend API works perfectly when tested separately (e.g., using Thunderclient).

Key Symptoms:

The request returns undefined data.

The console indicates the status as pending, but not successful or erroneous.

Proper backend response has been verified outside of the front-end implementation.

Solution Steps

To resolve this issue, we need to fine-tune our use of the RTK Query to ensure we're handling the async data fetching correctly. Here are the steps to follow:

Step 1: Use the Correct Invocation of the Query

In your original snippet, you may be trying to use the query directly. Instead, you should await the query to handle the asynchronous nature of data fetching. Consider revising your data retrieval code like this:

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Step 2: Implementing the Async Function

Wrap the invocation in an async function where the getUserData query is called. Ensure you call this function at a suitable place in your component, usually within a useEffect, if you want it to initiate based on specific conditions or changes in state. For example:

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

Step 3: Verify Data Handling

Inspect how you use the returned data. Inside your useEffect, check that you are correctly updating your state with the data once it's successfully fetched:

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

Conclusion

By ensuring that your RTK Query is invoked correctly using await, you can address the issue of receiving undefined data in your requests. Additionally, wrapping the call in an asynchronous function and strategically using useEffect can optimize your data handling approach. When working with state management and data fetching in React, always remember the asynchronous nature of these operations.

If you encounter similar issues, revisit your async handling, confirm your API configurations, and check that your Redux state updates accordingly. Happy coding!