https://github.com/caolan/events

Browser port of the node.js events module
https://github.com/caolan/events

Last synced: 17 days ago
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Browser port of the node.js events module

• Host: GitHub
• URL: https://github.com/caolan/events
• Owner: caolan
• Created: 2012-11-02T11:18:17.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2012-11-02T11:21:25.000Z (about 12 years ago)
• Last Synced: 2024-10-11T07:35:11.535Z (about 1 month ago)
• Language: JavaScript
• Size: 133 KB
• Stars: 8
• Watchers: 3
• Forks: 2
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

        
## Events module

This is a AMD port of the node.js events module. Many objects and

modules emit events and these are instances of events.EventEmitter.

Functions can be attached to objects, to be executed when an event is

emitted. These functions are called listeners.

### API

#### events.EventEmitter

When an EventEmitter instance experiences an error, the typical action is to

emit an 'error' event. Error events are treated as a special case. If there

is no listener for it, then the default action is for the error to throw.

All EventEmitters emit the event 'newListener' when new listeners are added.

```javascript

define('myModule', ['events'], function(events) {

// create an event emitter

var emitter = new events.EventEmitter();

});

```

#### emitter.setMaxListeners(n)

By default EventEmitters will print a warning if more than 10 listeners are

added for a particular event. This is a useful default which helps finding

memory leaks. Obviously not all Emitters should be limited to 10. This

function allows that to be increased. Set to zero for unlimited.

* __n__ - _Number_ - The maximum number of listeners

#### emitter.emit(event, [arg1], [arg2], [...])

Execute each of the listeners in order with the supplied arguments.

* __event__ - _String_ - The event name/id to fire

#### emitter.on(event, listener) | emitter.addListener(event, listener)

Adds a listener to the end of the listeners array for the specified event.

* __event__ - _String_ - The event name/id to listen for

* __listener__ - _Function_ - The function to bind to the event

```javascript

session.on('change', function (userCtx) {

    console.log('session changed!');

});

```

#### emitter.once(event, listener)

Adds a one time listener for the event. This listener is invoked only the

next time the event is fired, after which it is removed.

* __event-__ - _String_ - The event name/id to listen for

* __listener__ - _Function_ - The function to bind to the event

```javascript

db.once('unauthorized', function (req) {

    // this event listener will fire once, then be unbound

});

```

#### emitter.removeListener(event, listener)

Remove a listener from the listener array for the specified event. Caution:

changes array indices in the listener array behind the listener.

* __event__ - _String_ - The event name/id to remove the listener from

* __listener__ - _Function_ - The listener function to remove

```javascript

var callback = function (init) {

    console.log('duality app loaded');

};

devents.on('init', callback);

// ...

devents.removeListener('init', callback);

```

#### emitter.removeAllListeners([event])

Removes all listeners, or those of the specified event.

* __event__ - _String_ - Event name/id to remove all listeners for (optional)

#### emitter.listeners(event)

Returns an array of listeners for the specified event. This array can be

manipulated, e.g. to remove listeners.

* __events__ - _String_ - The event name/id to return listeners for

```javascript

session.on('change', function (stream) {

    console.log('session changed');

});

console.log(util.inspect(session.listeners('change'))); // [ [Function] ]

```