1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
<!DOCTYPE html>
<meta name="viewport" content="width=device-width,initial-scale=1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/intersection-observer-test-utils.js"></script>
<style>
body, html {
margin: 0;
}
pre, #log {
position: absolute;
top: 0;
left: 200px;
}
#target {
width: 100px;
height: 100px;
background-color: green;
}
#occluder {
width: 100px;
height: 100px;
background-color: blue;
}
</style>
<div id="target"></div>
<div id="occluder"></div>
<script>
async_test(t => {
let entries = [];
let delay = 100;
let target = document.getElementById("target");
let occluder = document.getElementById("occluder");
assert_true(!!target, "target exists");
assert_true(!!occluder, "occluder exists");
let observer = new IntersectionObserver(function(changes) {
entries = entries.concat(changes)
}, {trackVisibility: true, delay: delay});
observer.observe(target);
entries = entries.concat(observer.takeRecords());
assert_equals(entries.length, 0, "No initial notifications.");
// The first notification should be sent without delay.
waitForNotification(t, t.step_func(step0));
function waitForDelay(timerExpiredBeforeLastFrame, nextStep) {
requestAnimationFrame(t.step_func(() => {
if (timerExpiredBeforeLastFrame) {
// New notifications should have been generated during the previous
// frame and delivered by now.
assert_equals(entries.length, 2);
assert_greater_than(entries[1].time - entries[0].time, delay);
assert_false(entries[1].isVisible);
nextStep();
} else {
// Observer may not have updated yet. Wait for next frame.
let timerExpired = performance.now() - entries[0].time >= delay;
waitForDelay(timerExpired, nextStep);
}
}));
}
function step0() {
assert_equals(entries.length, 1);
assert_true(entries[0].isVisible);
// This should trigger a notification on the next run.
occluder.style.marginTop = "-10px";
// Enter a rAF loop until the delay timer expires.
waitForDelay(false, step1);
}
function step1() {
occluder.style.marginTop = "10px";
// This style invalidation should cause a frame to run before the observer
// can generate a notification (due to delay parameter). Make sure the
// notification will still be generated even if we don't force more frames
// with a rAF loop.
t.step_timeout(() => {
assert_equals(entries.length, 3);
assert_true(entries[0].isVisible);
t.done();
}, 2 * delay);
}
}, "'delay' parameter throttles frequency of notifications.");
</script>
|
