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45 lines
2.1 KiB
HTML
45 lines
2.1 KiB
HTML
<!DOCTYPE HTML>
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<meta charset=utf-8>
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<title>Layout Instability entries are not available via the performance timeline</title>
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<body>
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<style>
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#myDiv { position: relative; width: 300px; height: 100px; }
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</style>
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<div id='myDiv'></div>
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<!-- Delay onload by inserting a slow image.-->
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<img src="resources/slow-image.py">
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<script>
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async_test(function (t) {
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if (!window.LayoutShift)
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assert_unreached('LayoutShift entries are not supported');
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const startTime = performance.now();
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new PerformanceObserver(list => {
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const endTime = performance.now();
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assert_equals(list.getEntries().length, 1);
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const entry = list.getEntries()[0];
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assert_equals(entry.entryType, "layout-shift");
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assert_equals(entry.name, "");
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assert_greater_than_equal(entry.startTime, startTime)
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assert_less_than_equal(entry.startTime, endTime)
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assert_equals(entry.duration, 0.0);
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const maxDimension = Math.max(document.documentElement.clientWidth,
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document.documentElement.clientHeight);
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// The layout shift value should be:
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// 300 * (100 + 60) * (60 / maxDimension) / viewport size.
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assert_equals(entry.value, 300 * (100 + 60) * (60 / maxDimension) /
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(document.documentElement.clientWidth * document.documentElement.clientHeight));
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// The entry should not be available via getEntries* methods.
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assert_equals(performance.getEntriesByType('layout-shift').length, 0, 'getEntriesByType should have no layout-shift entries');
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assert_equals(performance.getEntriesByName('', 'layout-shift').length, 0, 'getEntriesByName should have no layout-shift entries');
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assert_equals(performance.getEntries().filter(e => e.entryType === 'layout-shift').length, 0, 'getEntries should have no layout-shift entries');
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t.done();
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}).observe({type: 'layout-shift'});
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// Modify the position of the div.
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document.getElementById('myDiv').style = "top: 60px";
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}, 'Layout shift before onload is not buffered into the performance timeline.');
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</script>
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</body>
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