100 lines
4.2 KiB
JavaScript
100 lines
4.2 KiB
JavaScript
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/**
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* @license
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* Copyright 2020 Google Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/**
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* Priorities for the announce function.
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*/
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export var AnnouncerPriority;
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(function (AnnouncerPriority) {
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AnnouncerPriority["POLITE"] = "polite";
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AnnouncerPriority["ASSERTIVE"] = "assertive";
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})(AnnouncerPriority || (AnnouncerPriority = {}));
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/**
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* Data attribute added to live region element.
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*/
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export var DATA_MDC_DOM_ANNOUNCE = 'data-mdc-dom-announce';
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/**
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* Announces the given message with optional priority, defaulting to "polite"
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*/
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export function announce(message, options) {
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Announcer.getInstance().say(message, options);
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}
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var Announcer = /** @class */ (function () {
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// Constructor made private to ensure only the singleton is used
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function Announcer() {
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this.liveRegions = new Map();
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}
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Announcer.getInstance = function () {
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if (!Announcer.instance) {
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Announcer.instance = new Announcer();
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}
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return Announcer.instance;
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};
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Announcer.prototype.say = function (message, options) {
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var _a, _b;
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var priority = (_a = options === null || options === void 0 ? void 0 : options.priority) !== null && _a !== void 0 ? _a : AnnouncerPriority.POLITE;
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var ownerDocument = (_b = options === null || options === void 0 ? void 0 : options.ownerDocument) !== null && _b !== void 0 ? _b : document;
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var liveRegion = this.getLiveRegion(priority, ownerDocument);
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// Reset the region to pick up the message, even if the message is the
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// exact same as before.
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liveRegion.textContent = '';
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// Timeout is necessary for screen readers like NVDA and VoiceOver.
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setTimeout(function () {
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liveRegion.textContent = message;
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ownerDocument.addEventListener('click', clearLiveRegion);
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}, 1);
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function clearLiveRegion() {
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liveRegion.textContent = '';
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ownerDocument.removeEventListener('click', clearLiveRegion);
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}
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};
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Announcer.prototype.getLiveRegion = function (priority, ownerDocument) {
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var documentLiveRegions = this.liveRegions.get(ownerDocument);
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if (!documentLiveRegions) {
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documentLiveRegions = new Map();
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this.liveRegions.set(ownerDocument, documentLiveRegions);
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}
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var existingLiveRegion = documentLiveRegions.get(priority);
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if (existingLiveRegion &&
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ownerDocument.body.contains(existingLiveRegion)) {
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return existingLiveRegion;
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}
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var liveRegion = this.createLiveRegion(priority, ownerDocument);
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documentLiveRegions.set(priority, liveRegion);
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return liveRegion;
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};
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Announcer.prototype.createLiveRegion = function (priority, ownerDocument) {
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var el = ownerDocument.createElement('div');
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el.style.position = 'absolute';
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el.style.top = '-9999px';
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el.style.left = '-9999px';
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el.style.height = '1px';
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el.style.overflow = 'hidden';
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el.setAttribute('aria-atomic', 'true');
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el.setAttribute('aria-live', priority);
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el.setAttribute(DATA_MDC_DOM_ANNOUNCE, 'true');
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ownerDocument.body.appendChild(el);
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return el;
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};
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return Announcer;
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}());
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//# sourceMappingURL=announce.js.map
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