forked from mirrors/gecko-dev
1f830c96da
# ignore-this-changeset Differential Revision: https://phabricator.services.mozilla.com/D36042 --HG-- extra : source : d3afcafdce650a6f36cebbc126ee93b17f13cf52
71 lines
2.1 KiB
JavaScript
71 lines
2.1 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* Define getters and setters for observedAttributes converted to camelCase and
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* trigger a batched aynchronous call to `render` upon observed
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* attribute/property changes.
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*/
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export default function ObservedPropertiesMixin(superClass) {
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return class ObservedProperties extends superClass {
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static kebabToCamelCase(name) {
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return name.replace(/-([a-z])/g, ($0, $1) => $1.toUpperCase());
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}
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constructor() {
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super();
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this._observedPropertiesMixin = {
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pendingRender: false,
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};
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// Reflect property changes for `observedAttributes` to attributes.
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for (let name of this.constructor.observedAttributes || []) {
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if (name in this) {
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// Don't overwrite existing properties.
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continue;
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}
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// Convert attribute names from kebab-case to camelCase properties
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Object.defineProperty(this, ObservedProperties.kebabToCamelCase(name), {
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configurable: true,
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get() {
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return this.getAttribute(name);
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},
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set(value) {
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if (value === null || value === undefined || value === false) {
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this.removeAttribute(name);
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} else {
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this.setAttribute(name, value);
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}
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},
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});
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}
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}
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async _invalidateFromObservedPropertiesMixin() {
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if (this._observedPropertiesMixin.pendingRender) {
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return;
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}
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this._observedPropertiesMixin.pendingRender = true;
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await Promise.resolve();
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try {
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this.render();
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} finally {
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this._observedPropertiesMixin.pendingRender = false;
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}
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}
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attributeChangedCallback(attr, oldValue, newValue) {
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if (super.attributeChangedCallback) {
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super.attributeChangedCallback(attr, oldValue, newValue);
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}
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if (oldValue === newValue) {
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return;
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}
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this._invalidateFromObservedPropertiesMixin();
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}
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};
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}
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