Скачать или смотреть Chaining Promises: How to Effectively Upload Files and Handle Responses in React

Master the art of `promise chaining` in JavaScript with our detailed guide. Learn how to upload files to the cloud and process responses efficiently in your React app!
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This video is based on the question https://stackoverflow.com/q/62999446/ asked by the user 'NevD' ( https://stackoverflow.com/u/11016660/ ) and on the answer https://stackoverflow.com/a/62999664/ provided by the user 'Bergi' ( https://stackoverflow.com/u/1048572/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Chaining Promises: How to Effectively Upload Files and Handle Responses in React

In today’s guide, we’re tackling a common challenge faced by many developers working with file uploads in React applications. If you’re working with forms that allow users to upload files, you might find yourself needing to manage asynchronous operations, especially when interfacing with services like Cloudinary. The task at hand involves uploading a file, waiting for a response, and then proceeding to send that data to your backend database. This process heavily relies on promise chaining, which can sometimes lead to confusion, especially if you’re new to asynchronous JavaScript.

The Problem

You have a React form that allows users to upload a file. Once a file is selected, you're saving it into your state and toggling a boolean value. When the form is submitted, you need to:

Upload the file to Cloudinary

Wait for the response that contains the URL and public ID of the uploaded file

Append this information to the form data that will be sent to your backend

Despite your best efforts, you find that the promise chaining you implemented isn’t working as expected, and you're left with an empty form data object.

Understanding Promise Chaining

Promise chaining is a powerful feature in JavaScript that allows you to run asynchronous tasks in a sequence. Let's break down how to effectively implement this in your file uploading logic within a React component.

Step 1: Initialize Form Data

Start by creating an init function to initialize your form data:

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

Step 2: Upload File to Cloudinary

Next, move on to defining the function that handles the file upload to Cloudinary. Here’s where the key adjustment needs to be made in your code:

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

Step 3: Chaining the Promises

Now, when you're ready to handle the form submission, tie it all together using promise chaining:

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

Conclusion

By properly returning promises within your upLoadToCL function and maintaining a clear promise chain, you can effectively manage file uploads and subsequent operations in your React application. Remember to always return the result of your promises to ensure that the following operations receive the correct data.

This simple yet effective method ensures a smooth user experience when handling file uploads, and understanding promise chaining will undoubtedly enhance your overall JavaScript skills.

Now, go ahead and apply this knowledge to your applications and create seamless file upload functionalities. Happy coding!