/**
- * @file
- * Adds an HTML element and method to trigger audio UAs to read system messages.
- *
- * Use {@link Drupal.announce} to indicate to screen reader users that an
- * element on the page has changed state. For instance, if clicking a link
- * loads 10 more items into a list, one might announce the change like this.
- *
- * @example
- * $('#search-list')
- * .on('itemInsert', function (event, data) {
- * // Insert the new items.
- * $(data.container.el).append(data.items.el);
- * // Announce the change to the page contents.
- * Drupal.announce(Drupal.t('@count items added to @container',
- * {'@count': data.items.length, '@container': data.container.title}
- * ));
- * });
- */
+* DO NOT EDIT THIS FILE.
+* See the following change record for more information,
+* https://www.drupal.org/node/2815083
+* @preserve
+**/
(function (Drupal, debounce) {
-
- 'use strict';
-
- var liveElement;
+ var liveElement = void 0;
var announcements = [];
- /**
- * Builds a div element with the aria-live attribute and add it to the DOM.
- *
- * @type {Drupal~behavior}
- *
- * @prop {Drupal~behaviorAttach} attach
- * Attaches the behavior for drupalAnnouce.
- */
Drupal.behaviors.drupalAnnounce = {
- attach: function (context) {
- // Create only one aria-live element.
+ attach: function attach(context) {
if (!liveElement) {
liveElement = document.createElement('div');
liveElement.id = 'drupal-live-announce';
}
};
- /**
- * Concatenates announcements to a single string; appends to the live region.
- */
function announce() {
var text = [];
var priority = 'polite';
- var announcement;
+ var announcement = void 0;
- // Create an array of announcement strings to be joined and appended to the
- // aria live region.
var il = announcements.length;
for (var i = 0; i < il; i++) {
announcement = announcements.pop();
text.unshift(announcement.text);
- // If any of the announcements has a priority of assertive then the group
- // of joined announcements will have this priority.
+
if (announcement.priority === 'assertive') {
priority = 'assertive';
}
}
if (text.length) {
- // Clear the liveElement so that repeated strings will be read.
liveElement.innerHTML = '';
- // Set the busy state to true until the node changes are complete.
+
liveElement.setAttribute('aria-busy', 'true');
- // Set the priority to assertive, or default to polite.
+
liveElement.setAttribute('aria-live', priority);
- // Print the text to the live region. Text should be run through
- // Drupal.t() before being passed to Drupal.announce().
+
liveElement.innerHTML = text.join('\n');
- // The live text area is updated. Allow the AT to announce the text.
+
liveElement.setAttribute('aria-busy', 'false');
}
}
- /**
- * Triggers audio UAs to read the supplied text.
- *
- * The aria-live region will only read the text that currently populates its
- * text node. Replacing text quickly in rapid calls to announce results in
- * only the text from the most recent call to {@link Drupal.announce} being
- * read. By wrapping the call to announce in a debounce function, we allow for
- * time for multiple calls to {@link Drupal.announce} to queue up their
- * messages. These messages are then joined and append to the aria-live region
- * as one text node.
- *
- * @param {string} text
- * A string to be read by the UA.
- * @param {string} [priority='polite']
- * A string to indicate the priority of the message. Can be either
- * 'polite' or 'assertive'.
- *
- * @return {function}
- * The return of the call to debounce.
- *
- * @see http://www.w3.org/WAI/PF/aria-practices/#liveprops
- */
Drupal.announce = function (text, priority) {
- // Save the text and priority into a closure variable. Multiple simultaneous
- // announcements will be concatenated and read in sequence.
announcements.push({
text: text,
priority: priority
});
- // Immediately invoke the function that debounce returns. 200 ms is right at
- // the cusp where humans notice a pause, so we will wait
- // at most this much time before the set of queued announcements is read.
- return (debounce(announce, 200)());
+
+ return debounce(announce, 200)();
};
-}(Drupal, Drupal.debounce));
+})(Drupal, Drupal.debounce);
\ No newline at end of file