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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /html/webappapis/scripting/event-loops/task_microtask_ordering.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<title>Task and Microtask Ordering </title>
<link rel=author title="Joshua Bell" href="mailto:jsbell@google.com">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/common.js"></script>
<div class="outer">
<div class="inner"></div>
</div>
<script>
log_test(function(t, log) {
log('script start');
setTimeout(function() {
log('setTimeout');
}, 0);
Promise.resolve().then(function() {
log('promise1');
}).then(function() {
log('promise2');
});
log('script end');
}, [
'script start',
'script end',
'promise1',
'promise2',
'setTimeout'
], 'Basic task and microtask ordering');
log_test(function(t, log) {
// Let's get hold of those elements
var outer = document.querySelector('.outer');
var inner = document.querySelector('.inner');
// Let's listen for attribute changes on the
// outer element
new MutationObserver(function() {
log('mutate');
}).observe(outer, {
attributes: true
});
// Here's a click listener...
function onClick() {
log('click');
setTimeout(function() {
log('timeout');
}, 0);
Promise.resolve().then(function() {
log('promise');
});
outer.setAttribute('data-random', Math.random());
}
// ...which we'll attach to both elements
inner.addEventListener('click', onClick);
outer.addEventListener('click', onClick);
// Note that this will behave differently than a real click,
// since the dispatch is synchronous and microtasks will not
// run between event bubbling steps.
inner.click();
}, [
'click',
'click',
'promise',
'mutate',
'promise',
'timeout',
'timeout'
], 'Level 1 bossfight (synthetic click)');
</script>