The hash property of the URLPattern interface is a string containing the pattern used to match the fragment 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 books/:id for the hash part. This pattern matches any fragment that starts with books/ and ends with an arbitrary string identifier.

const pattern = new URLPattern("https://example.org#books/:id");
console.log(pattern.hash); // 'books/:id'