The port property of the URLPattern interface is a string containing the pattern used to match the port 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 (80|443|8080) for the port part. This pattern matches the port 80, 443, and 8080.

const pattern = new URLPattern({ port: "(80|443|8080)" });
console.log(pattern.port); // '(80|443|8080)'