sg-event-emitter/README.md

Simple service registry

# Event Emitter
Very simple class allowing for dispatch custom events in DOM-like style. It's tested in production apps on both browser and node.

## Usage

All available methods are:
  - `addEventListener(name: string, listener: ()=>void)` - adds a new listener to given event
  - `removeEventListener(name: string, listener: ()=>void)` - removes registered listener for given event. You have to pass exactly the same function as passed previously to `addEventListener`.
  - `dispatchEvent(name: string)` - dispatches given event
  - `settle(host: any)` - links `addEventListener` and `removeEventListener` from EventEmitter instance to given host object. This allows you to create really encapsulated EventEmitter instance and expose only these two public methods.  

```js

var EventEmitter = require('sg-event-emitter').EventEmitter;
//or
import {EventEmitter} from 'sg-event-emitter';

class Foo {
    constructor () {
        this._eventEmitter = new EventEmitter();
        this._eventEmitter.settle(this); //from now this object has 
                                         //`addEventListener` and `removeEventListener` methods
    }
    
    makeSomeAction () {
        this._eventEmitter.dispatchEvent('myEvent');
    }
}

var foo = new Foo();
var listener = _ => console.log('dispatched');
foo.addEventListener('myEvent', listener);

foo.makeSomeAction();  //logs 'dispatched'

foo.removeEventListener('myEvent', listener);

foo.makeSomeAction();  //doesn't log anything
```