How to Store Firestore Arrays in React Native

Learn how to effectively store Firestore array data in your React Native app using best coding practices and hooks.
---
This video is based on the question https://stackoverflow.com/q/67422909/ asked by the user 'fusunnn' ( https://stackoverflow.com/u/15455946/ ) and on the answer https://stackoverflow.com/a/67423206/ provided by the user 'Dallas Baker' ( https://stackoverflow.com/u/15357622/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Trying to store FireStore array in React Native?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Storing Firestore Arrays in React Native: A Step-by-Step Guide

If you're working on a React Native application and need to handle Firestore data, particularly arrays, you may encounter some challenges along the way. A common problem developers face is how to correctly fetch and store Firestore data in their application state without running into issues like infinite loops or getting empty results. In this post, we will walk through the common pitfalls and provide clear, practical solutions to effectively store Firestore arrays in your React Native applications.

Understanding the Problem

Let's start by reviewing the initial attempts to pull data from a Firestore document. The provided code snippets illustrate several different approaches the developer used, but they encountered issues that hindered their progress:

Attempt to Push Data to an Array:

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

Issue: This method resulted in an empty data array when logged, as the get() call is asynchronous and may not resolve before logging.

Using State Hook to Set Data:

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

Issue: This implementation led to an infinite loop and continuously updated the state because it was likely being called each render cycle.

Direct Promise Call:

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

Issue: This approach simply returned a pending promise, without actual document data.

What We Need to Do

To effectively fetch and save data from Firestore within a React Native component, we can make use of hooks alongside the Firestore API. Below, we outline a refined approach based on best practices.

A Better Approach: Using React State and useEffect Hook

1. Setting Up Your State

First, make sure you have your state management set up correctly using the useState hook. This will allow you to store the data received from Firestore.

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

2. Define Data Fetching Logic with useEffect

Using the useEffect hook ensures that your data fetching logic runs after the component mounts. You can fetch the data from Firestore as follows:

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

3. Understanding the Fetch Process

When you access a Firestore collection, it provides a snapshot of the data. This snapshot contains all the documents in the collection. You can map over these documents to extract useful information.

snapshot.docs: This array contains each document retrieved from the Firestore collection.

Mapping: We create a new array of objects where each object includes the document ID alongside its data.

4. Adding New Data

If you need to add new data to the Firestore, you can use the following approach:

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

Conclusion

By following the above methods, you can effectively manage Firestore data in your React Native applications. It's crucial to remember to use the useEffect hook for any asynchronous calls to prevent infinite loops and to ensure that data is retrieved correctly before being set into your React state.

With these strategies in hand, you can confidently work with arrays and other data types in Firestore, optimizing your application for better performance and user experience.

Feel free to reach out if you have any questions or further issues regarding Firestore with React Native!

Видео How to Store Firestore Arrays in React Native канала vlogize