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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /custom-elements/parser/parser-fallsback-to-unknown-element.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>Custom Elements: Changes to the HTML parser</title>
<meta name="author" title="Ryosuke Niwa" href="mailto:rniwa@webkit.org">
<meta name="assert" content="HTML parser must fallback to creating a HTMLUnknownElement when a custom element construction fails">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<div id="log"></div>
<script>
setup({allow_uncaught_exception:true});
class ReturnsTextNode extends HTMLElement {
constructor() {
super();
return document.createTextNode('some text');
}
};
customElements.define('returns-text', ReturnsTextNode);
class ReturnsNonElementObject extends HTMLElement {
constructor() {
super();
return {};
}
};
customElements.define('returns-non-element-object', ReturnsNonElementObject);
class LacksSuperCall extends HTMLElement {
constructor() { }
};
customElements.define('lacks-super-call', LacksSuperCall);
class ThrowsException extends HTMLElement {
constructor() {
throw 'Bad';
}
};
customElements.define('throws-exception', ThrowsException);
</script>
<returns-text></returns-text>
<returns-non-element-object></returns-non-element-object>
<lacks-super-call></lacks-super-call>
<throws-exception></throws-exception>
<script>
test(function () {
var instance = document.querySelector('returns-text');
assert_false(instance instanceof ReturnsTextNode, 'HTML parser must NOT instantiate a custom element when the constructor returns a Text node');
assert_true(instance instanceof HTMLElement, 'The fallback element created by HTML parser must be an instance of HTMLElement');
assert_true(instance instanceof HTMLUnknownElement, 'The fallback element created by HTML parser must be an instance of HTMLUnknownElement');
}, 'HTML parser must create a fallback HTMLUnknownElement when a custom element constructor returns a Text node');
test(function () {
var instance = document.querySelector('returns-non-element-object');
assert_false(instance instanceof ReturnsNonElementObject, 'HTML parser must NOT instantiate a custom element when the constructor returns a non-Element object');
assert_true(instance instanceof HTMLElement, 'The fallback element created by HTML parser must be an instance of HTMLElement');
assert_true(instance instanceof HTMLUnknownElement, 'The fallback element created by HTML parser must be an instance of HTMLUnknownElement');
}, 'HTML parser must create a fallback HTMLUnknownElement when a custom element constructor returns non-Element object');
test(function () {
var instance = document.querySelector('lacks-super-call');
assert_false(instance instanceof LacksSuperCall, 'HTML parser must NOT instantiate a custom element when the constructor does not call super()');
assert_true(instance instanceof HTMLElement, 'The fallback element created by HTML parser must be an instance of HTMLElement');
assert_true(instance instanceof HTMLUnknownElement, 'The fallback element created by HTML parser must be an instance of HTMLUnknownElement');
}, 'HTML parser must create a fallback HTMLUnknownElement when a custom element constructor does not call super()');
test(function () {
var instance = document.querySelector('throws-exception');
assert_false(instance instanceof ThrowsException, 'HTML parser must NOT instantiate a custom element when the constructor throws an exception');
assert_true(instance instanceof HTMLElement, 'The fallback element created by HTML parser must be an instance of HTMLElement');
assert_true(instance instanceof HTMLUnknownElement, 'The fallback element created by HTML parser must be an instance of HTMLUnknownElement');
}, 'HTML parser must create a fallback HTMLUnknownElement when a custom element constructor throws an exception');
</script>
</body>
</html>