<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Event Timing: toJSON</title>
<body>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script src=/resources/testdriver.js></script>
<script src=/resources/testdriver-vendor.js></script>
<script src=resources/event-timing-test-utils.js></script>
<button id='button'>Generate a 'click' event</button>
<script>
  async_test(function (t) {
    assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
    const observer = new PerformanceObserver(
      t.step_func_done(function(entryList) {
        const entry = entryList.getEntries()[0];
        assert_equals(typeof(entry.toJSON), 'function');
        const json = entry.toJSON();
        assert_equals(typeof(json), 'object');
        const keys = [
          // PerformanceEntry
          'name',
          'entryType',
          'startTime',
          'duration',
          // PerformanceEventTiming
          'processingStart',
          'processingEnd',
          'cancelable',
          'target',
        ];
        for (const key of keys) {
          assert_equals(json[key], entry[key],
            'PerformanceEventTiming ${key} entry does not match its toJSON value');
        }
      })
    );
    observer.observe({type: 'event'});
    clickAndBlockMain('button');
  }, 'Test toJSON() in PerformanceEventTiming.');
</script>
</body>