mozilla-release/testing/web-platform/tests/wake-lock/wakelock-type.https.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>WakeLockType Test</title>
<link rel="help" href="https://w3c.github.io/wake-lock/">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<script>

promise_test(async t => {
  const wakeLock = await navigator.getWakeLock("screen");
  assert_equals(wakeLock.type, "screen");
}, "Test that wakeLock.type is 'screen' when screen wake lock is invoked");

promise_test(async t => {
  const wakeLock = await navigator.getWakeLock("system");
  assert_equals(wakeLock.type, "system");
}, "Test that wakeLock.type is 'system' when system wake lock is invoked");

promise_test(t => {
  return promise_rejects(t, new TypeError(), navigator.getWakeLock());
}, "'TypeError' is thrown when set an empty wake lock type");

promise_test(t => {
  return promise_rejects(t, new TypeError(), navigator.getWakeLock("unsupported"));
}, "'TypeError' is thrown when set an unsupported wake lock type");

</script>