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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /largest-contentful-paint/update-on-style-change.tentative.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset="utf-8">
<title>LargestContentfulPaint entries should generate for updates to previous LargestContentfulPaint nodes.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
promise_test(() => {
assert_implements(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented");
let countLcp = 0;
let firstLcp = null;
const timeoutPromise = new Promise(resolve => step_timeout(() => {
resolve(new Error('Did not observe two LCP entries'))
}, 3 * 1000));
const testPromise = new Promise(resolve => {
new PerformanceObserver(list => {
const entries = list.getEntries();
for (const entry of entries) {
++countLcp;
assert_equals(entry.entryType, 'largest-contentful-paint');
assert_equals(entry.id, 'text');
if (countLcp == 1) {
firstLcp = entry;
} else if (countLcp == 2) {
assert_more_than(entry.startTime, firstLcp.startTime);
assert_more_than(entry.size, firstLcp.size);
resolve();
}
}
}).observe({ entryTypes: ['largest-contentful-paint'] });
});
return Promise.race([timeoutPromise, testPromise]);
})
</script>
<div id="text">text</div>
<link rel="stylesheet" href="/resources/slow-style-change.py">
</body>