custom-elements/attribute-changed-callback.html

<!DOCTYPE html>
<html>
<head>
<title>Custom Elements: attributeChangedCallback</title>
<meta name="author" title="Ryosuke Niwa" href="mailto:rniwa@webkit.org">
<meta name="assert" content="attributeChangedCallback must be enqueued whenever custom element's attribute is added, changed or removed">
<link rel="help" href="https://w3c.github.io/webcomponents/spec/custom/#dfn-attribute-changed-callback">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/custom-elements-helpers.js"></script>
</head>
<body>
<div id="log"></div>
<parser-created-element title></parser-created-element>
<script>

var customElement = define_new_custom_element(['title', 'id', 'r']);

test(function () {
    const instance = document.createElement(customElement.name);
    assert_array_equals(customElement.takeLog().types(), ['constructed']);

    instance.setAttribute('title', 'foo');
    assert_equals(instance.getAttribute('title'), 'foo');
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: null, newValue: 'foo', namespace: null});

    instance.removeAttribute('title');
    assert_equals(instance.getAttribute('title'), null);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: 'foo', newValue: null, namespace: null});
}, 'setAttribute and removeAttribute must enqueue and invoke attributeChangedCallback');

test(function () {
    var instance = document.createElement(customElement.name);
    assert_array_equals(customElement.takeLog().types(), ['constructed']);

    instance.setAttributeNS('http://www.w3.org/2000/svg', 'title', 'hello');
    assert_equals(instance.getAttribute('title'), 'hello');
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: null, newValue: 'hello', namespace: 'http://www.w3.org/2000/svg'});

    instance.removeAttributeNS('http://www.w3.org/2000/svg', 'title');
    assert_equals(instance.getAttribute('title'), null);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: 'hello', newValue: null, namespace: 'http://www.w3.org/2000/svg'});
}, 'setAttributeNS and removeAttributeNS must enqueue and invoke attributeChangedCallback');

test(function () {
    var instance = document.createElement(customElement.name);
    assert_array_equals(customElement.takeLog().types(), ['constructed']);

    var attr = document.createAttribute('id');
    attr.value = 'bar';
    instance.setAttributeNode(attr);

    assert_equals(instance.getAttribute('id'), 'bar');
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'id', oldValue: null, newValue: 'bar', namespace: null});

    instance.removeAttributeNode(attr);
    assert_equals(instance.getAttribute('id'), null);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'id', oldValue: 'bar', newValue: null, namespace: null});
}, 'setAttributeNode and removeAttributeNode must enqueue and invoke attributeChangedCallback for an HTML attribute');

test(function () {
    const instance = document.createElement(customElement.name);
    assert_array_equals(customElement.takeLog().types(), ['constructed']);

    const attr = document.createAttributeNS('http://www.w3.org/2000/svg', 'r');
    attr.value = '100';
    instance.setAttributeNode(attr);

    assert_equals(instance.getAttribute('r'), '100');
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'r', oldValue: null, newValue: '100', namespace: 'http://www.w3.org/2000/svg'});

    instance.removeAttributeNode(attr);
    assert_equals(instance.getAttribute('r'), null);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'r', oldValue: '100', newValue: null, namespace: 'http://www.w3.org/2000/svg'});
}, 'setAttributeNode and removeAttributeNS must enqueue and invoke attributeChangedCallback for an SVG attribute');

test(function () {
    const instance = document.createElement(customElement.name);
    assert_array_equals(customElement.takeLog().types(), ['constructed']);

    instance.toggleAttribute('title', true);
    assert_equals(instance.hasAttribute('title'), true);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: null, newValue: '', namespace: null});

    instance.toggleAttribute('title');
    assert_equals(instance.hasAttribute('title'), false);
    var logEntries = customElement.takeLog();
    assert_array_equals(logEntries.types(), ['attributeChanged']);
    assert_attribute_log_entry(logEntries.last(), {name: 'title', oldValue: '', newValue: null, namespace: null});
}, 'toggleAttribute must enqueue and invoke attributeChangedCallback');

test(function () {
    const callsToOld = [];
    const callsToNew = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        callsToOld.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['title'];
    customElements.define('element-with-mutated-attribute-changed-callback', CustomElement);
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        callsToNew.push(create_attribute_changed_callback_log(this, ...args));
    }

    const instance = document.createElement('element-with-mutated-attribute-changed-callback');
    instance.setAttribute('title', 'hi');
    assert_equals(instance.getAttribute('title'), 'hi');
    assert_array_equals(callsToNew, []);
    assert_equals(callsToOld.length, 1);
    assert_attribute_log_entry(callsToOld[0], {name: 'title', oldValue: null, newValue: 'hi', namespace: null});
}, 'Mutating attributeChangedCallback after calling customElements.define must not affect the callback being invoked');

test(function () {
    const calls = [];
    class CustomElement extends HTMLElement {
        attributeChangedCallback(...args) {
            calls.push(create_attribute_changed_callback_log(this, ...args));
        }
    }
    CustomElement.observedAttributes = ['title'];
    customElements.define('element-not-observing-id-attribute', CustomElement);

    const instance = document.createElement('element-not-observing-id-attribute');
    assert_equals(calls.length, 0);
    instance.setAttribute('title', 'hi');
    assert_equals(calls.length, 1);
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: 'hi', namespace: null});
    instance.setAttribute('id', 'some');
    assert_equals(calls.length, 1);
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: 'hi', namespace: null});
}, 'attributedChangedCallback must not be invoked when the observed attributes does not contain the attribute');

test(function () {
    const calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['title', 'lang'];
    customElements.define('element-with-mutated-observed-attributes', CustomElement);
    CustomElement.observedAttributes = ['title', 'id'];

    const instance = document.createElement('element-with-mutated-observed-attributes');
    instance.setAttribute('title', 'hi');
    assert_equals(calls.length, 1);
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: 'hi', namespace: null});

    instance.setAttribute('id', 'some');
    assert_equals(calls.length, 1);

    instance.setAttribute('lang', 'en');
    assert_equals(calls.length, 2);
    assert_attribute_log_entry(calls[1], {name: 'lang', oldValue: null, newValue: 'en', namespace: null});
}, 'Mutating observedAttributes after calling customElements.define must not affect the set of attributes for which attributedChangedCallback is invoked');

test(function () {
    var calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = { [Symbol.iterator]: function *() { yield 'lang'; yield 'style'; } };
    customElements.define('element-with-generator-observed-attributes', CustomElement);

    var instance = document.createElement('element-with-generator-observed-attributes');
    instance.setAttribute('lang', 'en');
    assert_equals(calls.length, 1);
    assert_attribute_log_entry(calls[0], {name: 'lang', oldValue: null, newValue: 'en', namespace: null});

    instance.setAttribute('lang', 'ja');
    assert_equals(calls.length, 2);
    assert_attribute_log_entry(calls[1], {name: 'lang', oldValue: 'en', newValue: 'ja', namespace: null});

    instance.setAttribute('title', 'hello');
    assert_equals(calls.length, 2);

    instance.setAttribute('style', 'font-size: 2rem');
    assert_equals(calls.length, 3);
    assert_attribute_log_entry(calls[2], {name: 'style', oldValue: null, newValue: 'font-size: 2rem', namespace: null});
}, 'attributedChangedCallback must be enqueued for attributes specified in a non-Array iterable observedAttributes');

test(function () {
    var calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['style'];
    customElements.define('element-with-style-attribute-observation', CustomElement);

    var instance = document.createElement('element-with-style-attribute-observation');
    assert_equals(calls.length, 0);

    instance.style.fontSize = '10px';
    assert_equals(calls.length, 1);
    assert_attribute_log_entry(calls[0], {name: 'style', oldValue: null, newValue: 'font-size: 10px;', namespace: null});

    instance.style.fontSize = '20px';
    assert_equals(calls.length, 2);
    assert_attribute_log_entry(calls[1], {name: 'style', oldValue: 'font-size: 10px;', newValue: 'font-size: 20px;', namespace: null});

}, 'attributedChangedCallback must be enqueued for style attribute change by mutating inline style declaration');

test(function () {
    var calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['title'];
    customElements.define('element-with-no-style-attribute-observation', CustomElement);

    var instance = document.createElement('element-with-no-style-attribute-observation');
    assert_equals(calls.length, 0);
    instance.style.fontSize = '10px';
    assert_equals(calls.length, 0);
    instance.title = 'hello';
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: 'hello', namespace: null});
}, 'attributedChangedCallback must not be enqueued when mutating inline style declaration if the style attribute is not observed');

test(function () {
    var calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['title'];
    customElements.define('parser-created-element', CustomElement);
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: '', namespace: null});
}, 'Upgrading a parser created element must enqueue and invoke attributeChangedCallback for an HTML attribute');

test(function () {
    var calls = [];
    class CustomElement extends HTMLElement { }
    CustomElement.prototype.attributeChangedCallback = function (...args) {
        calls.push(create_attribute_changed_callback_log(this, ...args));
    }
    CustomElement.observedAttributes = ['title'];
    customElements.define('cloned-element-with-attribute', CustomElement);

    var instance = document.createElement('cloned-element-with-attribute');
    assert_equals(calls.length, 0);
    instance.title = '';
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: '', namespace: null});

    calls = [];
    var clone = instance.cloneNode(false);
    assert_attribute_log_entry(calls[0], {name: 'title', oldValue: null, newValue: '', namespace: null});
}, 'Upgrading a cloned element must enqueue and invoke attributeChangedCallback for an HTML attribute');

</script>
</body>
</html>