@angular2-material/core/a11y/live-announcer.js

Angular 2 Material core

var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
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    return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __metadata = (this && this.__metadata) || function (k, v) {
    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
};
var __param = (this && this.__param) || function (paramIndex, decorator) {
    return function (target, key) { decorator(target, key, paramIndex); }
};
import { Injectable, OpaqueToken, Optional, Inject } from '@angular/core';
export var LIVE_ANNOUNCER_ELEMENT_TOKEN = new OpaqueToken('mdLiveAnnouncerElement');
export var MdLiveAnnouncer = (function () {
    function MdLiveAnnouncer(elementToken) {
        // We inject the live element as `any` because the constructor signature cannot reference
        // browser globals (HTMLElement) on non-browser environments, since having a class decorator
        // causes TypeScript to preserve the constructor signature types.
        this._liveElement = elementToken || this._createLiveElement();
    }
    /**
     * @param message Message to be announced to the screenreader
     * @param politeness The politeness of the announcer element.
     */
    MdLiveAnnouncer.prototype.announce = function (message, politeness) {
        var _this = this;
        if (politeness === void 0) { politeness = 'polite'; }
        this._liveElement.textContent = '';
        // TODO: ensure changing the politeness works on all environments we support.
        this._liveElement.setAttribute('aria-live', politeness);
        // This 100ms timeout is necessary for some browser + screen-reader combinations:
        // - Both JAWS and NVDA over IE11 will not announce anything without a non-zero timeout.
        // - With Chrome and IE11 with NVDA or JAWS, a repeated (identical) message won't be read a
        //   second time without clearing and then using a non-zero delay.
        // (using JAWS 17 at time of this writing).
        setTimeout(function () { return _this._liveElement.textContent = message; }, 100);
    };
    MdLiveAnnouncer.prototype._createLiveElement = function () {
        var liveEl = document.createElement('div');
        liveEl.classList.add('md-live-announcer');
        liveEl.setAttribute('aria-atomic', 'true');
        liveEl.setAttribute('aria-live', 'polite');
        document.body.appendChild(liveEl);
        return liveEl;
    };
    MdLiveAnnouncer = __decorate([
        Injectable(),
        __param(0, Optional()),
        __param(0, Inject(LIVE_ANNOUNCER_ELEMENT_TOKEN)), 
        __metadata('design:paramtypes', [Object])
    ], MdLiveAnnouncer);
    return MdLiveAnnouncer;
}());

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