HTTP response code in AJAX request in JavaScript

The status property of a response contains HTTP response code:

public/client.jsbutton.addEventListener('click', function() {
  fetch('/ajax.html').then(response => {
    console.log(response.status); // e.g. 200
  });
});

Задание 1

Print page text if 200 status code is received, and error if 404 is received.