The username property of the URLPattern interface is a string containing the pattern used to match the username part of a URL. This value may differ from the input to the constructor due to normalization.

A string.

The below example creates a URLPattern object with admin for the username part. This pattern matches only if the username part of the URL is admin.

const pattern = new URLPattern({ username: "admin" });
console.log(pattern.username); // 'admin'