<!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> <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 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'); </script> </body> </html>