How to Use documentId() in Firebase 9 Modular SDK for Firestore Queries

Описание: Learn how to properly implement `documentId()` in Firebase 9's modular SDK to retrieve documents by IDs seamlessly in your Firestore queries.
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How to Use documentId() in Firebase 9 Modular SDK for Firestore Queries

Transitioning from the traditional Firebase SDK to the new Firebase 9 modular SDK can pose some challenges, especially when it comes to syntax changes. A common issue faced by developers during this transition is how to correctly use the documentId() function to filter documents by their IDs. In this guide, we’ll explore how to effectively implement this functionality in your Firestore queries using the Firebase modular SDK.

Understanding the Problem

When working with Firebase SDK 8, retrieving documents using a specific set of document IDs was straightforward. However, with the introduction of Firebase 9's modular SDK, developers need to adjust their code to accommodate new methods and syntax.

Consider the following original code snippet from the Firebase SDK 8:

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With Firebase 9, the intent remains the same, but the approach requires a new understanding of how to craft queries with the modular SDK. Here's the attempt to modify it:

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The problem arises from not knowing how to use the documentId() function correctly, which can result in errors if not implemented properly.

Solution: Correct Syntax and Implementation

To solve your issue, let's break down the correct way to utilize documentId() in your query with Firebase 9.

Step 1: Import Required Functions

Ensure you import documentId from Firebase Firestore in your JavaScript file. Your import statement should look like this:

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Step 2: Initialize Firebase App

Make sure your Firebase app is initialized correctly. Setup your app as follows:

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Step 3: Construct the Query

Now, let’s correctly construct the query for retrieving documents using their IDs. Here’s how you should rewrite the function utilizing the correct query syntax:

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Step 4: Fetch Documents with the Query

Once you have the query set up, use it to get your documents with this function:

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Example Usage

Putting it all together, when you want to use the entire functionality, call getByIdQuery like so:

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This setup will correctly filter documents based on the given docIds array using the document ID in your Firestore collection.

Conclusion

Switching from Firebase SDK 8 to SDK 9 can be daunting, especially regarding query syntax. However, by understanding the correct way to implement documentId(), you can efficiently retrieve documents by their IDs while leveraging the modular nature of Firebase 9.

Feel free to reach out if you have any questions regarding implementing Firebase in your web applications!