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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();
}
}
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