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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /custom-elements/HTMLElement-constructor-customized-bulitins.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>Custom Elements: HTMLElement must allow subclassing</title>
<meta name="author" title="Ryosuke Niwa" href="mailto:rniwa@webkit.org">
<meta name="assert" content="HTMLElement must allow subclassing">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<div id="log"></div>
<script>
test(function() {
class SomeCustomElement extends HTMLElement {};
var getCount = 0;
var countingProxy = new Proxy(SomeCustomElement, {
get: function(target, prop, receiver) {
if (prop == "prototype") {
++getCount;
}
return Reflect.get(target, prop, receiver);
}
});
customElements.define("failure-counting-element-1", countingProxy,
{ extends: "button" });
// define() gets the prototype of the constructor it's passed, so
// reset the counter.
getCount = 0;
assert_throws_js(TypeError,
function () { new countingProxy() },
"Should not be able to construct an HTMLElement named 'button'");
assert_equals(getCount, 0, "Should never have gotten .prototype");
}, 'HTMLElement constructor must not get .prototype until it finishes its extends sanity checks, calling proxy constructor directly');
test(function() {
class SomeCustomElement extends HTMLElement {};
var getCount = 0;
var countingProxy = new Proxy(SomeCustomElement, {
get: function(target, prop, receiver) {
if (prop == "prototype") {
++getCount;
}
return Reflect.get(target, prop, receiver);
}
});
customElements.define("failure-counting-element-2", countingProxy,
{ extends: "button" });
// define() gets the prototype of the constructor it's passed, so
// reset the counter.
getCount = 0;
assert_throws_js(TypeError,
function () { Reflect.construct(HTMLElement, [], countingProxy) },
"Should not be able to construct an HTMLElement named 'button'");
assert_equals(getCount, 0, "Should never have gotten .prototype");
}, 'HTMLElement constructor must not get .prototype until it finishes its extends sanity checks, calling via Reflect');
</script>
</body>
</html>