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// Copyright 2018 the Deno authors. All rights reserved. MIT license.
import { test, assertEqual } from "./test_util.ts";
test(function addEventListenerTest() {
const document = new EventTarget();
assertEqual(document.addEventListener("x", null, false), undefined);
assertEqual(document.addEventListener("x", null, true), undefined);
assertEqual(document.addEventListener("x", null), undefined);
});
test(function constructedEventTargetCanBeUsedAsExpected() {
const target = new EventTarget();
const event = new Event("foo", { bubbles: true, cancelable: false });
let callCount = 0;
function listener(e) {
assertEqual(e, event);
++callCount;
}
target.addEventListener("foo", listener);
target.dispatchEvent(event);
assertEqual(callCount, 1);
target.dispatchEvent(event);
assertEqual(callCount, 2);
target.removeEventListener("foo", listener);
target.dispatchEvent(event);
assertEqual(callCount, 2);
});
test(function anEventTargetCanBeSubclassed() {
class NicerEventTarget extends EventTarget {
on(type, listener?, options?) {
this.addEventListener(type, listener, options);
}
off(type, callback?, options?) {
this.removeEventListener(type, callback, options);
}
}
const target = new NicerEventTarget();
const event = new Event("foo", { bubbles: true, cancelable: false });
let callCount = 0;
function listener() {
++callCount;
}
target.on("foo", listener);
assertEqual(callCount, 0);
target.off("foo", listener);
assertEqual(callCount, 0);
});
test(function removingNullEventListenerShouldSucceed() {
const document = new EventTarget();
assertEqual(document.removeEventListener("x", null, false), undefined);
assertEqual(document.removeEventListener("x", null, true), undefined);
assertEqual(document.removeEventListener("x", null), undefined);
});
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