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Diffstat (limited to 'browser/components/newtab/lib/PageEventManager.jsm')
-rw-r--r-- | browser/components/newtab/lib/PageEventManager.jsm | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/browser/components/newtab/lib/PageEventManager.jsm b/browser/components/newtab/lib/PageEventManager.jsm new file mode 100644 index 0000000000..58dc076829 --- /dev/null +++ b/browser/components/newtab/lib/PageEventManager.jsm @@ -0,0 +1,97 @@ +/* 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/. */ +"use strict"; + +/** + * 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. + */ +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(); + } +} + +const EXPORTED_SYMBOLS = ["PageEventManager"]; |