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