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Diffstat (limited to 'addon-sdk/source/lib/sdk/event/target.js')
-rw-r--r-- | addon-sdk/source/lib/sdk/event/target.js | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/addon-sdk/source/lib/sdk/event/target.js b/addon-sdk/source/lib/sdk/event/target.js new file mode 100644 index 000000000..3a1f5e5f0 --- /dev/null +++ b/addon-sdk/source/lib/sdk/event/target.js @@ -0,0 +1,74 @@ +/* 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": "stable" +}; + +const { on, once, off, setListeners } = require('./core'); +const { method, chainable } = require('../lang/functional/core'); +const { Class } = require('../core/heritage'); + +/** + * `EventTarget` is an exemplar for creating an objects that can be used to + * add / remove event listeners on them. Events on these objects may be emitted + * via `emit` function exported by 'event/core' module. + */ +const EventTarget = Class({ + /** + * Method initializes `this` event source. It goes through properties of a + * given `options` and registers listeners for the ones that look like an + * event listeners. + */ + /** + * Method initializes `this` event source. It goes through properties of a + * given `options` and registers listeners for the ones that look like an + * event listeners. + */ + initialize: function initialize(options) { + setListeners(this, options); + }, + /** + * Registers an event `listener` that is called every time events of + * specified `type` are emitted. + * @param {String} type + * The type of event. + * @param {Function} listener + * The listener function that processes the event. + * @example + * worker.on('message', function (data) { + * console.log('data received: ' + data) + * }) + */ + on: chainable(method(on)), + /** + * Registers an event `listener` that is called once the next time an event + * of the specified `type` is emitted. + * @param {String} type + * The type of the event. + * @param {Function} listener + * The listener function that processes the event. + */ + once: chainable(method(once)), + /** + * Removes an event `listener` for the given event `type`. + * @param {String} type + * The type of event. + * @param {Function} listener + * The listener function that processes the event. + */ + removeListener: function removeListener(type, listener) { + // Note: We can't just wrap `off` in `method` as we do it for other methods + // cause skipping a second or third argument will behave very differently + // than intended. This way we make sure all arguments are passed and only + // one listener is removed at most. + off(this, type, listener); + return this; + }, + // but we can wrap `off` here, as the semantics are the same + off: chainable(method(off)) + +}); +exports.EventTarget = EventTarget; |