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# Emitter [![Build Status](https://travis-ci.org/component/emitter.png)](https://travis-ci.org/component/emitter)
Event emitter component.
## Installation
``` $ component install component/emitter ```
## API
### Emitter(obj)
The `Emitter` may also be used as a mixin. For example a "plain" object may become an emitter, or you may extend an existing prototype.
As an `Emitter` instance:
```js var Emitter = require('emitter'); var emitter = new Emitter; emitter.emit('something'); ```
As a mixin:
```js var Emitter = require('emitter'); var user = { name: 'tobi' }; Emitter(user);
user.emit('im a user'); ```
As a prototype mixin:
```js var Emitter = require('emitter'); Emitter(User.prototype); ```
### Emitter#on(event, fn)
Register an `event` handler `fn`.
### Emitter#once(event, fn)
Register a single-shot `event` handler `fn`, removed immediately after it is invoked the first time.
### Emitter#off(event, fn)
* Pass `event` and `fn` to remove a listener. * Pass `event` to remove all listeners on that event. * Pass nothing to remove all listeners on all events.
### Emitter#emit(event, ...)
Emit an `event` with variable option args.
### Emitter#listeners(event)
Return an array of callbacks, or an empty array.
### Emitter#hasListeners(event)
Check if this emitter has `event` handlers.
## License
MIT
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