Скачать или смотреть Wait for All Promises to Resolve Before Updating State and Redirect in React with Firebase

Discover how to manage multiple file uploads in React and Firebase by ensuring all promises resolve before updating state and redirecting.
---
This video is based on the question https://stackoverflow.com/q/66885801/ asked by the user 'brunelli' ( https://stackoverflow.com/u/10604811/ ) and on the answer https://stackoverflow.com/a/66885859/ provided by the user 'Ori Drori' ( https://stackoverflow.com/u/5157454/ ) 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: Wait for all promises to resolve before updating state and redirect

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

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Wait for All Promises to Resolve Before Updating State and Redirect in React with Firebase

Working with file uploads in a React application can sometimes be tricky, especially when you need to perform actions only after all uploads have completed. If you're using Firebase Storage and React Hooks, you may have found yourself in a situation where you attempt to update your state and redirect the user before all files have been uploaded. In this guide, we'll explore how to effectively handle multiple file uploads and ensure that you perform state updates and redirects only when all promises have resolved.

The Problem: Premature State Updates

Imagine this scenario: You have a form in your application that allows users to upload multiple images to Firebase Storage. Once a file is uploaded, you want to update the UI to reflect changes (e.g., showing the success message or redirecting the user). However, if you attempt to update your state after each file upload completes, you might find that the state is being updated too early—before all files are uploaded. This can lead to incomplete actions and an inconsistent user experience.

Here's what your initial code might look like:

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

The Solution: Using Promise.all()

To ensure that you only update your state after all files have been uploaded, you can use Promise.all(). This method takes an array of promises and returns a single promise that resolves when all of the promises in the array are resolved. This way, you can confidently proceed with your operations only after all your file uploads have successfully completed.

Step-by-Step Implementation

Map Over the Files Array: Instead of using forEach, use map to create an array of promises for each file upload.

Wrap in Promise.all(): Use Promise.all() to wait for all file upload promises to resolve before proceeding.

Update State and Redirect: After the promise resolves, you can safely update your state and perform any redirects or additional actions.

Here’s how your updated handleSubmit function would look:

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

Conclusion

By using Promise.all(), you can manage multiple asynchronous operations more effectively in your React applications. This approach allows you to wait for all promises—such as file uploads to Firebase—to resolve before updating your UI or redirecting users, ensuring a smoother and more reliable user experience.

In conclusion, don’t let premature state updates hinder your app's functionality. With the above guide, you can confidently handle multiple file uploads while keeping your application state in sync.