CustomElementRegistry-constructor-and-callbacks-are-held-strongly.html

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This WPT test may be referenced by the following Test IDs:
- /custom-elements/CustomElementRegistry-constructor-and-callbacks-are-held-strongly.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<meta charset="utf-8">

<title>CustomElementInterface holds constructors and callbacks strongly, preventing them from being GCed if there are no other references</title>

<link rel="help" href="https://html.spec.whatwg.org/multipage/custom-elements.html#concept-custom-element-definition-lifecycle-callbacks">

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="/common/gc.js"></script>

<body>

<div id="customElementsRoot"></div>

<iframe id="emptyIframe" srcdoc></iframe>

<script>

"use strict";

const tagNames = [...new Array(100)].map((_, i) => `x-foo${i}`);

const delay = (t, ms) => new Promise(resolve => { t.step_timeout(resolve, ms); });

const connectedCallbackCalls = new Set;

const disconnectedCallbackCalls = new Set;

const attributeChangedCallbackCalls = new Set;

const adoptedCallbackCalls = new Set;

for (const tagName of tagNames) {

    const constructor = class extends HTMLElement {

        connectedCallback() { connectedCallbackCalls.add(tagName); }

        disconnectedCallback() { disconnectedCallbackCalls.add(tagName); }

        attributeChangedCallback() { attributeChangedCallbackCalls.add(tagName); }

        adoptedCallback() { adoptedCallbackCalls.add(tagName); }

};

    constructor.observedAttributes = ["foo"];

    customElements.define(tagName, constructor);

    delete constructor.prototype.connectedCallback;

    delete constructor.prototype.disconnectedCallback;

    delete constructor.prototype.attributeChangedCallback;

    delete constructor.prototype.adoptedCallback;

promise_test(async t => {

    await garbageCollect();

    assert_true(tagNames.every(tagName => typeof customElements.get(tagName) === "function"));

}, "constructor");

promise_test(async t => {

    await garbageCollect();

    for (const tagName of tagNames) {

        customElementsRoot.append(document.createElement(tagName));

    await delay(t, 10);

    assert_equals(connectedCallbackCalls.size, tagNames.length);

}, "connectedCallback");

promise_test(async t => {

    await garbageCollect();

    for (const xFoo of customElementsRoot.children) {

        xFoo.setAttribute("foo", "bar");

    await delay(t, 10);

    assert_equals(attributeChangedCallbackCalls.size, tagNames.length);

}, "attributeChangedCallback");

promise_test(async t => {

    await garbageCollect();

    customElementsRoot.innerHTML = "";

    await delay(t, 10);

    assert_equals(disconnectedCallbackCalls.size, tagNames.length);

}, "disconnectedCallback");

promise_test(async t => {

    await garbageCollect();

    for (const tagName of tagNames) {

        emptyIframe.contentDocument.adoptNode(document.createElement(tagName));

    await delay(t, 10);

    assert_equals(adoptedCallbackCalls.size, tagNames.length);

}, "adoptedCallback");

</script>