Скачать или смотреть How to Assign a Token to the Authorization Header in Axios Interceptor?

Learn how to properly assign an authorization token to the header in an Axios interceptor, while avoiding TypeScript errors.
---
This video is based on the question https://stackoverflow.com/q/75168699/ asked by the user 'Alyamin Smail' ( https://stackoverflow.com/u/11141374/ ) and on the answer https://stackoverflow.com/a/75169100/ provided by the user 'Ishan' ( https://stackoverflow.com/u/2504989/ ) 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: how to assign a token to authorization header in axios interceptor?

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.
---
How to Assign a Token to the Authorization Header in Axios Interceptor?

When working with APIs in JavaScript, especially using libraries like Axios, adding an authorization token to your request is crucial for secure interactions. However, if you're using TypeScript, you might run into some issues, particularly with type safety. In this guide, we'll explore a common problem faced by developers when trying to assign a token to the authorization header in an Axios interceptor and provide a reliable solution.

The Problem

Let's say you are creating an Axios instance with specific configurations. Below is an example setup that includes a base URL and some default headers:

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

Next, you add an interceptor to include a token in the authorization header of every request:

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

However, you might encounter an error in TypeScript that says: "Object is possibly 'undefined'". This happens because TypeScript's type checking doesn't guarantee that the headers property exists on the config object. This can result in potential runtime issues if the property is indeed undefined.

The Solution

To resolve this error while ensuring your application runs smoothly, you need to implement a check for the headers property before trying to access it. Below is a revised version of your interceptor that includes this essential check:

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

Breakdown of the Solution

Check for the headers Property: Before you try to set the Authorization header, you should verify that the headers property exists on the config object. This prevents TypeScript from throwing an error.

Using async/await: The method getAccessToken() might be an asynchronous call, which means you'll need to wait for the token to be retrieved. Using async ensures that your code waits for this process to complete.

Safe Assignment: With the check in place, if the headers object somehow isn't defined, your code will skip the assignment, thus avoiding any runtime errors related to undefined objects.

Conclusion

Managing authorization headers in Axios when using TypeScript doesn't have to be a complicated task. By adding a simple conditional check for the headers property, you can ensure your application maintains type safety while still achieving the functionality you need. This small tweak can save you from encountering potentially crippling errors in your application.

By following best practices and being mindful of TypeScript’s type safety, you can effectively handle API requests with ease. Happy coding!