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# namespace-emitter
A small event emitter with namespaces.
Not meant as a replacement for node's events module, but as a small component for browser js.
## Install
npm install --save namespace-emitter
## Example
```js
var emitter = require('namespace-emitter')()
emitter.on('*', function () {
console.log('all events emitted', this.event)
})
emitter.on('example', function () {
console.log('example event emitted')
})
emitter.emit('example')
// -> example event emitted
// -> all events emitted example
emitter.on('demo', function () {
console.log('multiple events with `demo` namespace emitted', this.event)
})
emitter.emit('demo:cool')
// -> all events emitted demo:cool
// -> multiple events with `demo` namespace emitted demo:cool
emitter.emit('demo:awesome')
// -> all events emitted demo:awesome
// -> multiple events with `demo` namespace emitted demo:awesome
emitter.emit('demo:great')
// -> all events emitted demo:great
// -> multiple events with `demo` namespace emitted demo:great
```
## API
### createNamespaceEmitter
Create an event emitter with namespaces
**Examples**
```javascript
var emitter = require('./index')()
emitter.on('*', function () {
console.log('all events emitted', this.event)
})
emitter.on('example', function () {
console.log('example event emitted')
})
```
### emit
Emit an event. Optionally namespace the event. Handlers are fired in the order in which they were added with exact matches taking precedence. Separate the namespace and event with a `:`
**Parameters**
- `event` **String** – the name of the event, with optional namespace
- `data` **...Any** – data variables that will be passed as arguments to the event listener
**Examples**
```javascript
emitter.emit('example')
emitter.emit('demo:test')
emitter.emit('data', { example: true}, 'a string', 1)
```
### off
Stop listening to an event. Stop all listeners on an event by only passing the event name. Stop a single listener by passing that event handler as a callback.
You must be explicit about what will be unsubscribed: `emitter.off('demo')` will unsubscribe an `emitter.on('demo')` listener,
`emitter.off('demo:example')` will unsubscribe an `emitter.on('demo:example')` listener
**Parameters**
- `event` **String**
- `fn` **[Function]** – the specific handler
**Examples**
```javascript
emitter.off('example')
emitter.off('demo', function () {})
```
### on
Create en event listener.
**Parameters**
- `event` **String**
- `fn` **Function**
**Examples**
```javascript
emitter.on('example', function () {})
emitter.on('demo', function () {})
```
### once
Create en event listener that fires once.
**Parameters**
- `event` **String**
- `fn` **Function**
**Examples**
```javascript
emitter.once('example', function () {})
emitter.once('demo', function () {})
```
## License
[MIT](LICENSE.md)