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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /dom/events/remove-all-listeners.html - WPT Dashboard Interop Dashboard
<!doctype html>
<title>Various edge cases where listeners are removed during iteration</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
test(function() {
var type = "foo";
var target = document.createElement("div");
var listener1CallCount = 0;
var listener2CallCount = 0;
var listener3CallCount = 0;
function listener1() {
listener1CallCount++;
target.removeEventListener(type, listener1);
target.removeEventListener(type, listener2);
target.addEventListener(type, listener3);
}
function listener2() {
listener2CallCount++;
}
function listener3() {
listener3CallCount++;
}
target.addEventListener(type, listener1);
target.addEventListener(type, listener2);
// Dispatch the event. Only listener1 should be called because
// it removes listener2. And listener3 is added when we've already
// started iterating, so it shouldn't be called either.
target.dispatchEvent(new Event(type));
assert_equals(listener1CallCount, 1);
assert_equals(listener2CallCount, 0);
assert_equals(listener3CallCount, 0);
// Now that only listener3 is set, dispatch another event. Only
// listener3 should be called.
target.dispatchEvent(new Event(type));
assert_equals(listener1CallCount, 1);
assert_equals(listener2CallCount, 0);
assert_equals(listener3CallCount, 1);
}, "Removing all listeners and then adding a new one should work.");
test(function() {
var type = "foo";
var target = document.createElement("div");
var listener1CallCount = 0;
var listener2CallCount = 0;
var listener3CallCount = 0;
function listener1() {
listener1CallCount++;
// Recursively dispatch another event from this listener.
// This will only call listener2 because listener1 is a "once" listener.
target.dispatchEvent(new Event(type));
assert_equals(listener1CallCount, 1);
assert_equals(listener2CallCount, 1);
assert_equals(listener3CallCount, 0);
// Now all listeners are removed - the two "once" listeners have already both
// been called once. Add another listener.
target.addEventListener(type, listener3);
}
function listener2() {
listener2CallCount++;
}
function listener3() {
listener3CallCount++;
}
// Add two "once" listeners.
target.addEventListener(type, listener1, { once: true });
target.addEventListener(type, listener2, { once: true });
// Dispatch the event.
target.dispatchEvent(new Event(type));
// The listener call counts should still match what they were
// at the end of listener1.
assert_equals(listener1CallCount, 1);
assert_equals(listener2CallCount, 1);
assert_equals(listener3CallCount, 0);
// Now that only listener3 is set, dispatch another event. Only
// listener3 should be called.
target.dispatchEvent(new Event(type));
assert_equals(listener1CallCount, 1);
assert_equals(listener2CallCount, 1);
assert_equals(listener3CallCount, 1);
}, "Nested usage of once listeners should work.");
</script>