You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
98 lines
3.3 KiB
98 lines
3.3 KiB
# event-emitter |
|
## Environment agnostic event emitter |
|
|
|
### Installation |
|
|
|
$ npm install event-emitter |
|
|
|
To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: [Browserify](http://browserify.org/), [Webmake](https://github.com/medikoo/modules-webmake) or [Webpack](http://webpack.github.io/) |
|
|
|
### Usage |
|
|
|
```javascript |
|
var ee = require('event-emitter'); |
|
|
|
var MyClass = function () { /* .. */ }; |
|
ee(MyClass.prototype); // All instances of MyClass will expose event-emitter interface |
|
|
|
var emitter = new MyClass(), listener; |
|
|
|
emitter.on('test', listener = function (args) { |
|
// … react to 'test' event |
|
}); |
|
|
|
emitter.once('test', function (args) { |
|
// … react to first 'test' event (invoked only once!) |
|
}); |
|
|
|
emitter.emit('test', arg1, arg2/*…args*/); // Two above listeners invoked |
|
emitter.emit('test', arg1, arg2/*…args*/); // Only first listener invoked |
|
|
|
emitter.off('test', listener); // Removed first listener |
|
emitter.emit('test', arg1, arg2/*…args*/); // No listeners invoked |
|
``` |
|
### Additional utilities |
|
|
|
#### allOff(obj) _(event-emitter/all-off)_ |
|
|
|
Removes all listeners from given event emitter object |
|
|
|
#### hasListeners(obj[, name]) _(event-emitter/has-listeners)_ |
|
|
|
Whether object has some listeners attached to the object. |
|
When `name` is provided, it checks listeners for specific event name |
|
|
|
```javascript |
|
var emitter = ee(); |
|
var hasListeners = require('event-emitter/has-listeners'); |
|
var listener = function () {}; |
|
|
|
hasListeners(emitter); // false |
|
|
|
emitter.on('foo', listener); |
|
hasListeners(emitter); // true |
|
hasListeners(emitter, 'foo'); // true |
|
hasListeners(emitter, 'bar'); // false |
|
|
|
emitter.off('foo', listener); |
|
hasListeners(emitter, 'foo'); // false |
|
``` |
|
|
|
#### pipe(source, target[, emitMethodName]) _(event-emitter/pipe)_ |
|
|
|
Pipes all events from _source_ emitter onto _target_ emitter (all events from _source_ emitter will be emitted also on _target_ emitter, but not other way). |
|
Returns _pipe_ object which exposes `pipe.close` function. Invoke it to close configured _pipe_. |
|
It works internally by redefinition of `emit` method, if in your interface this method is referenced differently, provide its name (or symbol) with third argument. |
|
|
|
#### unify(emitter1, emitter2) _(event-emitter/unify)_ |
|
|
|
Unifies event handling for two objects. Events emitted on _emitter1_ would be also emitted on _emitter2_, and other way back. |
|
Non reversible. |
|
|
|
```javascript |
|
var eeUnify = require('event-emitter/unify'); |
|
|
|
var emitter1 = ee(), listener1, listener3; |
|
var emitter2 = ee(), listener2, listener4; |
|
|
|
emitter1.on('test', listener1 = function () { }); |
|
emitter2.on('test', listener2 = function () { }); |
|
|
|
emitter1.emit('test'); // Invoked listener1 |
|
emitter2.emit('test'); // Invoked listener2 |
|
|
|
var unify = eeUnify(emitter1, emitter2); |
|
|
|
emitter1.emit('test'); // Invoked listener1 and listener2 |
|
emitter2.emit('test'); // Invoked listener1 and listener2 |
|
|
|
emitter1.on('test', listener3 = function () { }); |
|
emitter2.on('test', listener4 = function () { }); |
|
|
|
emitter1.emit('test'); // Invoked listener1, listener2, listener3 and listener4 |
|
emitter2.emit('test'); // Invoked listener1, listener2, listener3 and listener4 |
|
``` |
|
|
|
### Tests [![Build Status](https://travis-ci.org/medikoo/event-emitter.png)](https://travis-ci.org/medikoo/event-emitter) |
|
|
|
$ npm test
|
|
|