The Tor Browser: comparison addon-sdk/source/lib/sdk/dom/events.js

comparison: addon-sdk/source/lib/sdk/dom/events.js

addon-sdk/source/lib/sdk/dom/events.js

branch: TOR_BUG_3246
changeset 7: 129ffea94266

equal deleted inserted replaced

--1:000000000000
+:ede3c4b5ffdc
+/* 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";
+module.metadata = {
+"stability": "unstable"
+};
+// Utility function that returns copy of the given `text` with last character
+// removed if it is `"s"`.
+function singularify(text) {
+return text[text.length - 1] === "s" ? text.substr(0, text.length - 1) : text;
+}
+// Utility function that takes event type, argument is passed to
+// `document.createEvent` and returns name of the initializer method of the
+// given event. Please note that there are some event types whose initializer
+// methods can't be guessed by this function. For more details see following
+// link: https://developer.mozilla.org/En/DOM/Document.createEvent
+function getInitializerName(category) {
+return "init" + singularify(category);
+}
+/**
+* Registers an event `listener` on a given `element`, that will be called
+* when events of specified `type` is dispatched on the `element`.
+* @param {Element} element
+*    Dom element to register listener on.
+* @param {String} type
+*    A string representing the
+*    [event type](https://developer.mozilla.org/en/DOM/event.type) to
+*    listen for.
+* @param {Function} listener
+*    Function that is called whenever an event of the specified `type`
+*    occurs.
+* @param {Boolean} capture
+*    If true, indicates that the user wishes to initiate capture. After
+*    initiating capture, all events of the specified type will be dispatched
+*    to the registered listener before being dispatched to any `EventTarget`s
+*    beneath it in the DOM tree. Events which are bubbling upward through
+*    the tree will not trigger a listener designated to use capture.
+*    See [DOM Level 3 Events](http://www.w3.org/TR/DOM-Level-3-Events/#event-flow)
+*    for a detailed explanation.
+*/
+function on(element, type, listener, capture) {
+// `capture` defaults to `false`.
+capture = capture || false;
+element.addEventListener(type, listener, capture);
+}
+exports.on = on;
+/**
+* Registers an event `listener` on a given `element`, that will be called
+* only once, next time event of specified `type` is dispatched on the
+* `element`.
+* @param {Element} element
+*    Dom element to register listener on.
+* @param {String} type
+*    A string representing the
+*    [event type](https://developer.mozilla.org/en/DOM/event.type) to
+*    listen for.
+* @param {Function} listener
+*    Function that is called whenever an event of the specified `type`
+*    occurs.
+* @param {Boolean} capture
+*    If true, indicates that the user wishes to initiate capture. After
+*    initiating capture, all events of the specified type will be dispatched
+*    to the registered listener before being dispatched to any `EventTarget`s
+*    beneath it in the DOM tree. Events which are bubbling upward through
+*    the tree will not trigger a listener designated to use capture.
+*    See [DOM Level 3 Events](http://www.w3.org/TR/DOM-Level-3-Events/#event-flow)
+*    for a detailed explanation.
+*/
+function once(element, type, listener, capture) {
+on(element, type, function selfRemovableListener(event) {
+removeListener(element, type, selfRemovableListener, capture);
+listener.apply(this, arguments);
+}, capture);
+}
+exports.once = once;
+/**
+* Unregisters an event `listener` on a given `element` for the events of the
+* specified `type`.
+*
+* @param {Element} element
+*    Dom element to unregister listener from.
+* @param {String} type
+*    A string representing the
+*    [event type](https://developer.mozilla.org/en/DOM/event.type) to
+*    listen for.
+* @param {Function} listener
+*    Function that is called whenever an event of the specified `type`
+*    occurs.
+* @param {Boolean} capture
+*    If true, indicates that the user wishes to initiate capture. After
+*    initiating capture, all events of the specified type will be dispatched
+*    to the registered listener before being dispatched to any `EventTarget`s
+*    beneath it in the DOM tree. Events which are bubbling upward through
+*    the tree will not trigger a listener designated to use capture.
+*    See [DOM Level 3 Events](http://www.w3.org/TR/DOM-Level-3-Events/#event-flow)
+*    for a detailed explanation.
+*/
+function removeListener(element, type, listener, capture) {
+element.removeEventListener(type, listener, capture);
+}
+exports.removeListener = removeListener;
+/**
+* Emits event of the specified `type` and `category` on the given `element`.
+* Specified `settings` are used to initialize event before dispatching it.
+* @param {Element} element
+*    Dom element to dispatch event on.
+* @param {String} type
+*    A string representing the
+*    [event type](https://developer.mozilla.org/en/DOM/event.type).
+* @param {Object} options
+*    Options object containing following properties:
+*    - `category`: String passed to the `document.createEvent`. Option is
+*      optional and defaults to "UIEvents".
+*    - `initializer`: If passed it will be used as name of the method used
+*      to initialize event. If omitted name will be generated from the
+*      `category` field by prefixing it with `"init"` and removing last
+*      character if it matches `"s"`.
+*    - `settings`: Array of settings that are forwarded to the event
+*      initializer after firs `type` argument.
+* @see https://developer.mozilla.org/En/DOM/Document.createEvent
+*/
+function emit(element, type, { category, initializer, settings }) {
+category = category || "UIEvents";
+initializer = initializer || getInitializerName(category);
+let document = element.ownerDocument;
+let event = document.createEvent(category);
+event[initializer].apply(event, [type].concat(settings));
+element.dispatchEvent(event);
+};
+exports.emit = emit;