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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Methods for setting up and tearing down page event listeners. These are used
+ * to dismiss Feature Callouts when the callout's anchor element is clicked.
+ */
+export class PageEventManager {
+ /**
+ * A set of parameters defining a page event listener.
+ * @typedef {Object} PageEventListenerParams
+ * @property {String} type Event type string e.g. `click`
+ * @property {String} selectors Target selector, e.g. `tag.class, #id[attr]`
+ * @property {PageEventListenerOptions} [options] addEventListener options
+ *
+ * @typedef {Object} PageEventListenerOptions
+ * @property {Boolean} [capture] Use event capturing phase?
+ * @property {Boolean} [once] Remove listener after first event?
+ * @property {Boolean} [preventDefault] Inverted value for `passive` option
+ */
+
+ /**
+ * Maps event listener params to their abort controllers.
+ * @type {Map<PageEventListenerParams, AbortController>}
+ */
+ _listeners = new Map();
+
+ /**
+ * @param {Document} doc The document to look for event targets in
+ */
+ constructor(doc) {
+ this.doc = doc;
+ }
+
+ /**
+ * Adds a page event listener.
+ * @param {PageEventListenerParams} params
+ * @param {Function} callback Function to call when event is triggered
+ */
+ on(params, callback) {
+ if (this._listeners.has(params)) {
+ return;
+ }
+ const { type, selectors, options = {} } = params;
+ const controller = new AbortController();
+ const opt = {
+ capture: !!options.capture,
+ passive: !options.preventDefault,
+ signal: controller.signal,
+ };
+ const targets = this.doc.querySelectorAll(selectors);
+ for (const target of targets) {
+ target.addEventListener(type, callback, opt);
+ }
+ this._listeners.set(params, controller);
+ }
+
+ /**
+ * Removes a page event listener.
+ * @param {PageEventListenerParams} params
+ */
+ off(params) {
+ const controller = this._listeners.get(params);
+ if (!controller) {
+ return;
+ }
+ controller.abort();
+ this._listeners.delete(params);
+ }
+
+ /**
+ * Adds a page event listener that is removed after the first event.
+ * @param {PageEventListenerParams} params
+ * @param {Function} callback Function to call when event is triggered
+ */
+ once(params, callback) {
+ const wrappedCallback = (...args) => {
+ this.off(params);
+ callback(...args);
+ };
+ this.on(params, wrappedCallback);
+ }
+
+ /**
+ * Removes all page event listeners.
+ */
+ clear() {
+ for (const controller of this._listeners.values()) {
+ controller.abort();
+ }
+ this._listeners.clear();
+ }
+}