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// META: title=AddEventListenerOptions.once
"use strict";
test(function() {
var invoked_once = false;
var invoked_normal = false;
function handler_once() {
invoked_once = true;
}
function handler_normal() {
invoked_normal = true;
}
const et = new EventTarget();
et.addEventListener('test', handler_once, {once: true});
et.addEventListener('test', handler_normal);
et.dispatchEvent(new Event('test'));
assert_equals(invoked_once, true, "Once handler should be invoked");
assert_equals(invoked_normal, true, "Normal handler should be invoked");
invoked_once = false;
invoked_normal = false;
et.dispatchEvent(new Event('test'));
assert_equals(invoked_once, false, "Once handler shouldn't be invoked again");
assert_equals(invoked_normal, true, "Normal handler should be invoked again");
et.removeEventListener('test', handler_normal);
}, "Once listener should be invoked only once");
test(function() {
const et = new EventTarget();
var invoked_count = 0;
function handler() {
invoked_count++;
if (invoked_count == 1)
et.dispatchEvent(new Event('test'));
}
et.addEventListener('test', handler, {once: true});
et.dispatchEvent(new Event('test'));
assert_equals(invoked_count, 1, "Once handler should only be invoked once");
invoked_count = 0;
function handler2() {
invoked_count++;
if (invoked_count == 1)
et.addEventListener('test', handler2, {once: true});
if (invoked_count <= 2)
et.dispatchEvent(new Event('test'));
}
et.addEventListener('test', handler2, {once: true});
et.dispatchEvent(new Event('test'));
assert_equals(invoked_count, 2, "Once handler should only be invoked once after each adding");
}, "Once listener should be invoked only once even if the event is nested");
test(function() {
var invoked_count = 0;
function handler() {
invoked_count++;
}
const et = new EventTarget();
et.addEventListener('test', handler, {once: true});
et.addEventListener('test', handler);
et.dispatchEvent(new Event('test'));
assert_equals(invoked_count, 1, "The handler should only be added once");
invoked_count = 0;
et.dispatchEvent(new Event('test'));
assert_equals(invoked_count, 0, "The handler was added as a once listener");
invoked_count = 0;
et.addEventListener('test', handler, {once: true});
et.removeEventListener('test', handler);
et.dispatchEvent(new Event('test'));
assert_equals(invoked_count, 0, "The handler should have been removed");
}, "Once listener should be added / removed like normal listeners");
test(function() {
const et = new EventTarget();
var invoked_count = 0;
for (let n = 4; n > 0; n--) {
et.addEventListener('test', (e) => {
invoked_count++;
e.stopImmediatePropagation();
}, {once: true});
}
for (let n = 4; n > 0; n--) {
et.dispatchEvent(new Event('test'));
}
assert_equals(invoked_count, 4, "The listeners should be invoked");
}, "Multiple once listeners should be invoked even if the stopImmediatePropagation is set");
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