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Learn how to retrieve the updated Firestore document immediately after updating it in your React application without the need for a second query.
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This video is based on the question https://stackoverflow.com/q/64972850/ asked by the user 'Rob Terrell' ( https://stackoverflow.com/u/12548617/ ) and on the answer https://stackoverflow.com/a/64974125/ provided by the user 'Kevin Izuchukwu' ( https://stackoverflow.com/u/13460718/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Return the Updated Document After Firestore Update in React

When developing applications with Firestore, one common task is to update a user's document and retrieve the updated values. If you are working in a React application, you might wonder how to obtain the latest document data immediately after an update, without having to query Firestore again.

In this guide, we will explore the common challenge developers face when working with Firestore updates and provide an effective solution for handling this scenario.

The Problem: Retrieving Updated Document Data

Suppose you are working in a React application where you've initialized Firebase and are updating user documents stored in Firestore. You've written a function to handle the profile update, which looks something like this:

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

After successfully updating the document, you might be looking for a straightforward way to return a reference to the updated document. This leads us to a common question: Does .update() return a reference to the updated document?

Understanding the Limitation

Unfortunately, Firestore does not return updated values directly from the write methods (such as add, set, update, or delete).

The Solution: Making a Second Read

To retrieve the updated document data, you will need to call doc.ref.get() after your update operation. This will entail a second read to the Firestore servers, but it is the recommended approach to get the latest data accurately. Here’s how you can modify your code:

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

Key Considerations

Second Read Cost: Remember that Firestore charges for every read, including the additional call to retrieve the updated document. Keep this in mind while designing your application.

Error Handling: Ensure you handle errors gracefully, especially for the additional read operation, to avoid unexpected losses of user experience if something goes wrong.

Conclusion

While Firestore’s .update() method does not directly return an updated document reference, you can easily fetch the most recent data by using doc.ref.get() after making your update. This practice ensures you have real-time feedback from your database, allowing your application to reflect the latest information to your users effectively.

Now that you understand the process, you can apply it in your React applications and improve the interaction with Firestore!