largest-contentful-paint/toJSON.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Largest Contentful Paint: toJSON</title>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<p>Text!</p>
<script>
  async_test(function (t) {
    assert_implements(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented");
    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',
          // LargestContentfulPaint
          'renderTime',
          'loadTime',
          'size',
          'id',
          'url',
        ];
        for (const key of keys) {
          assert_equals(json[key], entry[key],
            'LargestContentfulPaint ${key} entry does not match its toJSON value');
        }
        assert_equals(json['element'], undefined, 'toJSON should not include element');
      })
    );
    observer.observe({type: 'largest-contentful-paint', buffered: true});
  }, 'Test toJSON() in LargestContentfulPaint.');
</script>
</body>