67 lines
2.4 KiB
HTML
67 lines
2.4 KiB
HTML
<!DOCTYPE HTML>
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<meta charset=utf-8>
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<title>Layout Instability: observe after user input</title>
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<body>
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<style>
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#myDiv { position: relative; width: 300px; height: 100px; background: blue; }
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/* Disable the button's focus ring, which otherwise expands its visual rect by
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* 1px on all sides, triggering a layout shift event.
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*/
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#button { outline: none; }
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</style>
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<div id='myDiv'></div>
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<button id='button'>Generate a 'click' event</button>
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<script src=/resources/testharness.js></script>
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<script src=/resources/testharnessreport.js></script>
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<script src=/resources/testdriver.js></script>
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<script src=/resources/testdriver-vendor.js></script>
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<script src=resources/util.js></script>
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<script src=/event-timing/resources/event-timing-test-utils.js></script>
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<script>
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let timeAfterClick;
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promise_test(async t => {
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assert_implements(window.LayoutShift, 'Layout Instability is not supported.');
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// Wait for the initial render to complete.
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await waitForAnimationFrames(2);
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const startTime = performance.now();
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const observerPromise = new Promise(resolve => {
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const observer = new PerformanceObserver(
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entryList => {
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resolve(entryList);
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}
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).observe({ entryTypes: ['layout-shift'] });
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});
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// User input event
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await clickAndBlockMain('button');
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// Modify the position of the div to trigger layout shift.
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document.getElementById('myDiv').style = "top: 60px";
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const layoutShiftEntryList = await observerPromise;
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const endTime = performance.now();
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assert_equals(layoutShiftEntryList.getEntries().length, 1);
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const entry = layoutShiftEntryList.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(entry.startTime, startTime,
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"The layout shift entry startTime should be greater than the test startTime.");
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assert_less_than(entry.startTime, endTime,
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"The layout shift entry startTime should be less than the test endTime.");
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assert_equals(entry.duration, 0.0);
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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, computeExpectedScore(300 * (100 + 60), 60));
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// We should see that there was a click input entry.
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assert_equals(entry.hadRecentInput, true);
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assert_less_than(entry.lastInputTime, entry.startTime,
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"The lastInputTime should be less than the layout shift startTime.");
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}, 'Layout shift right after user input is observable via PerformanceObserver.');
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</script>
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</body>
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