navigation-api/navigate-event/intercept-handler-throws.html

<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test(t => {
  const err = new TypeError("a message");
  let start_href = location.href;

  navigation.onnavigatesuccess = t.step_func_done(assert_unreached);
  navigation.onnavigateerror = t.step_func_done(e => {
    assert_equals(location.hash, "#1");
    assert_equals(e.constructor, ErrorEvent);
    assert_true(e.error === err);
    assert_true(e.message.includes("TypeError: a message"));
    assert_equals(e.filename, start_href);
    assert_greater_than(e.colno, 0);
    assert_greater_than(e.lineno, 0);
  });
  navigation.onnavigate = e => {
    e.intercept({ handler() { throw err; }});
  };

  location.href = "#1";
  assert_equals(location.hash, "#1");
}, "event.intercept() should abort if the handler throws");
</script>