102 lines
2.0 KiB
Markdown
102 lines
2.0 KiB
Markdown
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# EvEmitter
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_Lil' event emitter_ — add a little pub/sub
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EvEmitter adds publish/subscribe pattern to a browser class. It's a smaller version of [Olical/EventEmitter](https://github.com/Olical/EventEmitter). That EventEmitter is full featured, widely used, and great. This EvEmitter has just the base event functionality to power the event API in libraries like [Isotope](http://isotope.metafizzy.co), [Flickity](http://flickity.metafizzy.co), [Masonry](http://masonry.desandro.com), and [imagesLoaded](http://imagesloaded.desandro.com).
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## API
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``` js
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// Inherit prototype, IE8+
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MyClass.prototype = new EvEmitter();
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// Inherit prototype, IE9+
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MyClass.prototype = Object.create( EvEmitter.prototype );
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// Mixin prototype
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_.extend( MyClass.prototype, EvEmitter.prototype );
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// single instance
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var emitter = new EventEmitter();
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```
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### on
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Add an event listener.
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``` js
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emitter.on( eventName, listener )
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```
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+ `eventName` - _String_ - name of the event
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+ `listener` - _Function_
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### off
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Remove an event listener.
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``` js
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emitter.off( eventName, listener )
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```
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### once
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Add an event listener to be triggered only once.
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``` js
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emitter.once( eventName, listener )
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```
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### emitEvent
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Trigger an event.
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``` js
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emitter.emitEvent( eventName, args )
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```
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+ `eventName` - _String_ - name of the event
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+ `args` - _Array_ - arguments passed to listeners
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## Code example
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``` js
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// create event emitter
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var emitter = new EventEmitter();
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// listeners
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function hey( a, b, c ) {
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console.log( 'Hey', a, b, c )
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}
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function ho( a, b, c ) {
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console.log( 'Ho', a, b, c )
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}
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function letsGo( a, b, c ) {
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console.log( 'Lets go', a, b, c )
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}
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// bind listeners
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emitter.on( 'rock', hey )
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emitter.once( 'rock', ho )
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// trigger letsGo once
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emitter.on( 'rock', letsGo )
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// emit event
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emitter.emitEvent( 'rock', [ 1, 2, 3 ] )
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// => 'Hey', 1, 2, 3
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// => 'Ho', 1, 2, 3
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// => 'Lets go', 1, 2, 3
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// unbind
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emitter.off( 'rock', ho )
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emitter.emitEvent( 'rock', [ 4, 5, 6 ] )
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// => 'Hey' 4, 5, 6
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```
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## License
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EvEmitter is released under the [MIT License](http://desandro.mit-license.org/). Have at it.
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