presentation-api/controlling-ua/defaultRequest.https.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Setting a default presentation request</title>
<link rel="author" title="Tomoyuki Shimizu" href="https://github.com/tomoyukilabs">
<link rel="help" href="http://w3c.github.io/presentation-api/#controlling-user-agent">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<script>
  test(() => {
    assert_equals(navigator.presentation.defaultRequest, null, 'The initial value of the default presentation request is null.');

    const request = new PresentationRequest('https://example.org/');
    navigator.presentation.defaultRequest = request;
    assert_equals(navigator.presentation.defaultRequest, request, 'The default presentation request is set to an instance of PresentationRequest.');

    assert_throws_js(TypeError, () => {
      navigator.presentation.defaultRequest = {};
    }, 'The default presentation request cannot be set to any value but an instance of PresentationRequest or null.');

    navigator.presentation.defaultRequest = null;
    assert_equals(navigator.presentation.defaultRequest, null, 'The default presentation request is set to null.');
  });
</script>