only-observe-firstInput.html (1901B)
1 <!DOCTYPE html> 2 <html> 3 <meta charset=utf-8 /> 4 <title>Event Timing: only observe the first input</title> 5 <button id='button'>Generate a 'click' event</button> 6 <script src=/resources/testharness.js></script> 7 <script src=/resources/testharnessreport.js></script> 8 <script src=/resources/testdriver.js></script> 9 <script src=/resources/testdriver-vendor.js></script> 10 11 <script src=resources/event-timing-test-utils.js></script> 12 13 <script> 14 /* Test: 15 PerformanceObserver for first-input is registered 16 Click 1 17 Click 2 18 Wait 19 Expected result: 20 PerformanceObserver should observe one and only one entry. 21 */ 22 async_test(function(t) { 23 assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.'); 24 let hasObservedFirstInput = false; 25 new PerformanceObserver(t.step_func((entryList) => { 26 assert_false(hasObservedFirstInput); 27 hasObservedFirstInput = true; 28 const observedEntries = entryList.getEntries().filter( 29 entry => entry.name === 'pointerdown'); 30 assert_equals(observedEntries.length, 1); 31 assert_equals(observedEntries[0].entryType, 'first-input'); 32 assert_equals(observedEntries[0].name, 'pointerdown'); 33 })).observe({ entryTypes: ['first-input'] }); 34 on_event(window, 'load', () => { 35 clickAndBlockMain('button').then(() => { 36 clickAndBlockMain('button').then(wait).then( () => { 37 // After some wait, the PerformanceObserver should have processed both clicks. 38 // One and only one first-input entry should have been dispatched, so 39 // |hasObservedFirstInput| should be true. 40 t.step_timeout( () => { 41 assert_true(hasObservedFirstInput); 42 t.done(); 43 }, 10); 44 }); 45 }); 46 }); 47 }, 48 "Event Timing: check first-input for a PerformanceObserver observing only first-input." 49 ); 50 </script> 51 </html>