URL.username API in Node.js

Introduction to URL.username API in Node.js

When dealing with URLs that include authentication information, you might come across URLs formatted with embedded credentials such as a username. In Node.js, the URL class allows you to easily extract and modify various components of a URL, and the URL.username property is specifically designed to handle the username portion of the URL.

What is URL.username?

The URL.username property provides a way to access or set the username embedded in a URL. This is commonly used in situations where a URL includes credentials, typically in the format: https://username:password@hostname. With this property, you can work directly with just the username, without needing to manually parse the string.

Syntax of URL.username

// To get the username
url.username

// To set the username
url.username = 'newUsername'
    

Example: Getting the Username

Here’s a simple example of how to retrieve the username from a URL:

const { URL } = require('url');

const myURL = new URL('https://john:secret@host.com');
console.log(myURL.username); // Output: john
    

In this case, the username property returns "john", which was the username provided in the URL string.

Example: Setting a New Username

You can also update the username of a URL object easily:

const { URL } = require('url');

const myURL = new URL('https://host.com');
myURL.username = 'admin';

console.log(myURL.href); // Output: https://admin@host.com/
    

Here, we assign a new username "admin" to the URL, which updates the full URL string accordingly.

When to Use URL.username

Using URL.username is helpful in several use cases, including:

• Managing credentials: Parsing and updating authentication info in URLs securely.
• Generating URLs programmatically: Creating login URLs dynamically in backend services.
• Validating input: Ensuring URLs contain the correct credentials structure before processing.

Important Notes

• If the username is not set in the URL, the property will return an empty string.
• Changing the username directly updates the URL string when you access url.href.
• This property works only with URLs that include a valid protocol (e.g., http, https).

Conclusion

The URL.username API in Node.js simplifies working with user credentials in URLs. Whether you're parsing incoming URLs or generating secure URLs for API access, this property helps you manage the username portion cleanly and efficiently. It's a small but handy part of the powerful url module that makes Node.js development easier when dealing with web addresses.