Sister

Foundation for your emitter implementation.

I have observed that there is a tendency to write your own implementation of event emitter. I have written a starter pack for those wishing to improve upon existing variations of event emitter implementation.

Please submit your implementation to the index when you are done.

In All Seriousness

Sister is 0.5kb event emitter that does three things: on, off and trigger. It performs well (~18,313,548 operations/sec in browser). If you need something more advanced, consider one of the existing, mature alternatives.

Node

Download using NPM:

npm install sister --save

Browser

Download using Bower:

bower install sister --save

In browser, use gajus.Sister window object.

Methods

• emitter.on(event, handler)
• emitter.off(listener)
• emitter.trigger(event, data)

Parameters

• emitter Instance of the Sister() object.
• event Name of the event.
• handler A function to execute when the event is triggered.
• listener Event listener.

emitter.on(event, handler)

• Add handler for event.
• Return listener.

emitter.off(listener)

• Remove listener.

emitter.trigger(event, data)

• Invoke event listeners (in sequence) with the supplied argument.
• Return emitter.

Usage

var Sister = require('sister'),
    emitter = Sister(),
    listener;

listener = emitter.on('foo', console.log);
emitter.trigger('foo', 'bar');
emitter.off(listener);
emitter.trigger('foo', 'baz');

This example will print "bar" in the console.log.

Similar Libraries

There are several existing alternatives that you might want to consider before starting to write your own implementation of an event emitter.

| Repository | Stars | Forks | Commits | Last Commit | | --- | --- | --- | --- | --- | |asyncly/EventEmitter2| 846 | 92 | 321 | 2014-06-12 | |Wolfy87/EventEmitter| 711 | 102 | 628 | 2014-09-30 | |RobertWHurst/LucidJS| 375 | 15 | 141 | 2014-09-26 | |jeromeetienne/microevent.js| 284 | 57 | 17 | 2014-07-23 | |uxder/Radio| 242 | 20 | 47 | 2013-06-14 | |component/emitter| 150 | 52 | 69 | 2014-08-29 | |necolas/emitter.js| 75 | 3 | 51 | 2014-05-16 | |mkuklis/asEvented| 74 | 13 | 80 | 2014-01-10 | |FredyC/promised-land| 67 | 1 | 25 | 2014-09-05 | |postaljs/monologue.js| 66 | 6 | 32 | 2014-06-20 | |scottcorgan/tiny-emitter| 66 | 2 | 24 | 2014-09-16 | |primus/EventEmitter3| 57 | 7 | 76 | 2014-10-10 | |segmentio/wildcards| 56 | 2 | 21 | 2014-04-10 | |facebook/emitter| 50 | 12 | 6 | 2014-02-20 | |Gozala/events| 39 | 11 | 45 | 2014-08-29 | |danielstjules/pattern-emitter| 38 | 3 | 38 | 2014-04-25 | |hrsh7th/js-co-on| 31 | 0 | 12 | 2014-07-01 | |cpsubrian/node-eventflow| 22 | 5 | 44 | 2013-07-16 | |medikoo/event-emitter| 20 | 1 | 155 | 2014-08-22 | |component/channel| 19 | 1 | 20 | 2014-02-13 | |mixu/microee| 15 | 0 | 21 | 2014-02-27 | |qawemlilo/emitter| 14 | 2 | 26 | 2013-12-10 | |substack/node-ordered-emitter| 13 | 2 | 21 | 2013-07-11 | |godmodelabs/fwd| 12 | 1 | 23 | 2013-03-12 | |ericz/EventEmitter| 11 | 7 | 3 | 2013-02-08 | |fent/pauseable.js| 11 | 3 | 20 | 2014-07-29 | |defunctzombie/dom-events| 10 | 1 | 16 | 2013-11-20 | |bredele/emitter-queue| 10 | 0 | 14 | 2014-04-07 | |postaljs/monopost.js| 9 | 2 | 10 | 2013-02-04 | |addyosmani/polymer-eventemitter| 9 | 0 | 15 | 2014-01-24 | |busterjs/bane| 8 | 1 | 33 | 2013-11-23 | |fnando/emitter| 8 | 1 | 16 | 2014-10-01 | |sakabako/paperboy| 7 | 1 | 59 | 2014-10-01 | |Nicolab/node-ipc-events| 7 | 0 | 4 | 2014-07-02 | |fent/node-eventyoshi| 7 | 0 | 35 | 2014-07-29 | |yields/delegate-events| 7 | 0 | 2 | 2013-11-06 | |feross/re-emitter| 6 | 1 | 15 | 2014-07-23 | |dmotz/stream-snitch| 6 | 0 | 13 | 2014-09-07 | |jhermsmeier/emitter.js| 6 | 0 | 52 | 2014-05-19 | |hapijs/kilt| 5 | 1 | 17 | 2014-09-29 | |1000ch/EventEmitter| 5 | 0 | 23 | 2014-02-25 | |Raynos/eventemitter-light| 5 | 0 | 20 | 2012-08-04 | |mcollina/patrun-emitter| 5 | 0 | 26 | 2014-05-26 | |pgte/propagate| 5 | 0 | 12 | 2014-01-30 | |jonnywyatt/eventsWithPromises| 4 | 2 | 21 | 2014-08-26 | |oleics/node-caevents| 4 | 2 | 9 | 2012-04-09 | |lelandtseng/EventEmitter| 4 | 1 | 17 | 2013-10-19 | |petkaantonov/FastEmitter| 4 | 1 | 29 | 2013-10-22 | |Alex-ray/concierge| 4 | 0 | 33 | 2014-05-12 | |derekr/paganate| 4 | 0 | 13 | 2014-04-17 | |gdi2290/angular-event-emitter| 4 | 0 | 31 | 2014-07-19 | |maxponte/EventEmitter| 4 | 0 | 7 | 2014-08-08 | |iwillwen/node_emitter| 3 | 2 | 2 | 2012-03-10 | |IndigoUnited/js-events-emitter| 3 | 1 | 73 | 2014-04-18 | |kamicane/emi| 3 | 1 | 2 | 2012-03-06 | |olav/ee.js| 3 | 1 | 21 | 2014-02-13 | |vesln/evts| 3 | 1 | 14 | 2013-12-15 | |fent/node-newsemitter| 3 | 0 | 10 | 2014-07-29 | |yields/buffer-events| 3 | 0 | 4 | 2014-06-27 | |aconbere/evented| 2 | 2 | 10 | 2010-10-27 | |shokai/event_emitter.js| 2 | 2 | 39 | 2013-05-17 | |aluarosi/event0.js| 2 | 1 | 10 | 2014-03-17 | |benjreinhart/node-event-emitter| 2 | 1 | 5 | 2014-03-29 | |madimp/deferredEventEmitter| 2 | 1 | 6 | 2012-05-13 | |pierrec/node-ev| 2 | 1 | 13 | 2012-06-25 | |alexborisov/abNanoEvent| 2 | 0 | 5 | 2013-11-12 | |apily/emitter| 2 | 0 | 27 | 2014-06-19 | |eldargab/hooks-emitter| 2 | 0 | 5 | 2013-03-27 | |ericelliott/clctr| 2 | 0 | 8 | 2013-08-06 | |henrytseng/event-aggregator| 2 | 0 | 14 | 2014-03-05 | |ksdlck/Emitterarchy| 2 | 0 | 7 | 2012-01-18 | |pgte/boxed-emitter| 2 | 0 | 11 | 2012-12-31 | |rubenv/angular-tiny-eventemitter| 2 | 0 | 5 | 2014-07-25 | |ryanve/energy| 2 | 0 | 36 | 2014-05-10 | |steerapi/ti-event-emitter| 2 | 0 | 5 | 2011-12-29 | |tarunc/CollectionEventEmitter2| 2 | 0 | 2 | 2013-07-04 | |vinayakcs/eventEmitter| 2 | 0 | 11 | 2014-08-25 | |anthonyshort/emitter-manager| 1 | 2 | 12 | 2013-07-31 | |joaquimserafim/tiny-eventemitter| 1 | 2 | 7 | 2014-03-26 | |B-Vladi/EventEmitter| 1 | 1 | 111 | 2014-10-19 | |MatthewMueller/aemitter| 1 | 1 | 8 | 2014-05-24 | |chrisdickinson/estate| 1 | 1 | 7 | 2013-08-28 | |mccalltd/EventEmitter| 1 | 1 | 49 | 2014-01-04 | |UsabilityDynamics/node-object-emitter| 1 | 0 | 39 | 2014-08-30 | |asbjornenge/nanoemitter| 1 | 0 | 10 | 2014-05-12 | |buunguyen/evtify| 1 | 0 | 8 | 2014-03-09 | |cballou/jquery-eventemitter| 1 | 0 | 6 | 2014-02-10 | |enricomarino/events| 1 | 0 | 4 | 2011-10-31 | |erykpiast/angular-event-emitter| 1 | 0 | 7 | 2014-08-26 | |floatdrop/after-event| 1 | 0 | 9 | 2014-10-20 | |gummesson/evmit| 1 | 0 | 2 | 2014-04-26 | |hden/Bacon.EventEmitter| 1 | 0 | 5 | 2013-04-02 | |jaridmargolin/event-emitter.js| 1 | 0 | 6 | 2014-08-20 | |jdarling/hyjack| 1 | 0 | 28 | 2014-09-10 | |jharding/boomerang| 1 | 0 | 13 | 2013-07-09 | |jimgswang/EventEmitter| 1 | 0 | 44 | 2014-07-24 | |jkroso/dom-emitter| 1 | 0 | 48 | 2013-08-29 | |jls/emitJS| 1 | 0 | 9 | 2011-10-25 | |ksdlck/Emitting| 1 | 0 | 14 | 2012-01-19 | |maxhoffmann/emitter| 1 | 0 | 40 | 2014-08-20 | |npmcomponent/littlebitselectronics-EventEmitter2| 1 | 0 | 290 | 2013-08-13 | |nrn/nee| 1 | 0 | 4 | 2014-09-03 | |pete-otaqui/EventEmitter| 1 | 0 | 7 | 2011-05-24 | |pgte/switch-emitter| 1 | 0 | 9 | 2013-01-17 | |plediii/HevEmitter| 1 | 0 | 92 | 2014-09-30 | |rosylilly/EventEmitter.js| 1 | 0 | 5 | 2011-08-26 | |sjmulder/event-registrar| 1 | 0 | 3 | 2012-07-20 | |smagch/sprite| 1 | 0 | 10 | 2013-05-13 | |steelsojka/leafyjs| 1 | 0 | 23 | 2014-06-08 | |xwcoder/EventEmitter| 1 | 0 | 3 | 2014-09-14 | |Livefyre/event-emitter| 0 | 1 | 29 | 2014-09-24 | |evilharlequin/matter| 0 | 1 | 3 | 2014-07-25 | |ricardobeat/emmy| 0 | 1 | 9 | 2014-10-02 | |thibauts/eventemitter| 0 | 1 | 4 | 2014-06-25 | |AndreasMadsen/emitterpoint| 0 | 0 | 1 | 2013-08-27 | |Havvy/after-events| 0 | 0 | 1 | 2014-01-17 | |Kl0tl/events-emitter| 0 | 0 | 4 | 2014-01-12 | |LingyuCoder/EventEmitter| 0 | 0 | 7 | 2014-09-28 | |RangerMauve/mqtt-emitter| 0 | 0 | 8 | 2014-09-07 | |Raynos/cached-events| 0 | 0 | 1 | 2012-08-25 | |Raynos/multi-event| 0 | 0 | 5 | 2012-08-10 | |STRML/forward-emitter| 0 | 0 | 2 | 2014-06-30 | |SoftwareDevPro/EventEmitter.coffee| 0 | 0 | 3 | 2013-11-28 | |Tom32i/event-emitter.js| 0 | 0 | 9 | 2014-06-03 | |Wizcorp/events| 0 | 0 | 5 | 2014-03-10 | |alanshaw/funce-emitter| 0 | 0 | 10 | 2014-05-07 | |anchorjs/events| 0 | 0 | 28 | 2013-06-20 | |bendrucker/emit-then| 0 | 0 | 26 | 2014-10-11 | |bevacqua/contra.emitter| 0 | 0 | 7 | 2014-09-21 | |beyo/events| 0 | 0 | 10 | 2014-05-15 | |bmullan91/evt-emitter| 0 | 0 | 14 | 2014-10-19 | |browser-modules/event-emitter| 0 | 0 | 4 | 2014-07-20 | |brycebaril/eenano| 0 | 0 | 2 | 2014-08-16 | |btknorr/emitter-all| 0 | 0 | 14 | 2013-04-05 | |canvace/EventEmitter| 0 | 0 | 7 | 2013-10-26 | |chrisdickinson/every| 0 | 0 | 4 | 2013-02-19 | |chuckpreslar/broadcaster| 0 | 0 | 22 | 2013-07-06 | |cookfront/EventEmitter| 0 | 0 | 1 | 2014-07-19 | |coolbloke1324/emitter| 0 | 0 | 3 | 2014-03-26 | |coverslide/mkee| 0 | 0 | 8 | 2013-04-14 | |cybrown/SimpleEventEmitter| 0 | 0 | 3 | 2013-07-08 | |darlanalves/EventEmitter| 0 | 0 | 13 | 2014-10-11 | |devangpaliwal/eventemitter| 0 | 0 | 2 | 2013-07-28 | |dfcreative/emmy| 0 | 0 | 81 | 2014-10-15 | |dimik/EventEmitter| 0 | 0 | 8 | 2013-09-28 | |edubskiy/events.emitter.js| 0 | 0 | 2 | 2013-06-23 | |ericgj/logged-emitter| 0 | 0 | 2 | 2013-05-22 | |esatterwhite/node-pattern-emitter| 0 | 0 | 24 | 2014-05-08 | |eventEmitter/ee-event-emitter| 0 | 0 | 7 | 2014-08-24 | |exfm/event-emitter| 0 | 0 | 2 | 2012-09-07 | |fabiosantoscode/clientjs-event-emitter| 0 | 0 | 2 | 2013-01-22 | |fnobi/EventEmitter| 0 | 0 | 15 | 2014-08-12 | |fskreuz/MiniEvent| 0 | 0 | 3 | 2013-09-04 | |gaborsar/MicroEventEmitter| 0 | 0 | 6 | 2014-06-25 | |hachr/EventEmitter| 0 | 0 | 2 | 2014-05-21 | |jamesvsnowden/emitter| 0 | 0 | 9 | 2013-06-02 | |jbrumwell/jqevents| 0 | 0 | 4 | 2012-12-05 | |jdpanderson/OrderedEventEmitter| 0 | 0 | 3 | 2014-02-16 | |jillix/emitter| 0 | 0 | 21 | 2014-08-13 | |joechee/EventEmitter-async| 0 | 0 | 2 | 2014-09-27 | |kaerus-component/emitter| 0 | 0 | 23 | 2014-05-10 | |kalachevmax/semantic.events| 0 | 0 | 1 | 2014-06-22 | |kallaspriit/EventEmitter| 0 | 0 | 2 | 2013-08-08 | |lakenen/eemitter| 0 | 0 | 8 | 2014-06-26 | |madbook/easy-events| 0 | 0 | 2 | 2014-01-23 | |marcello3d/node-listenable| 0 | 0 | 1 | 2013-10-25 | |mateuspv/Events| 0 | 0 | 9 | 2014-05-21 | |mercmobily/EventEmitterCollector| 0 | 0 | 12 | 2013-11-23 | |mescoda/EventEmitter| 0 | 0 | 25 | 2014-03-18 | |michaelrhodes/event-relay| 0 | 0 | 5 | 2013-11-13 | |mpotra/events-async| 0 | 0 | 5 | 2014-05-11 | |mvantil/FutureEventEmitter| 0 | 0 | 3 | 2013-03-30 | |nathanfaucett/event_emitter| 0 | 0 | 28 | 2014-10-19 | |nathanmacinnes/edifice| 0 | 0 | 2 | 2014-04-28 | |neocoder/emmi| 0 | 0 | 1 | 2013-08-23 | |nib-health-funds/forward-events| 0 | 0 | 3 | 2014-07-14 | |niyazpk/EventEmitter| 0 | 0 | 16 | 2014-02-08 | |oliverroick/SuperSimpleEvents| 0 | 0 | 20 | 2014-10-12 | |pfraces-wip/pubsub| 0 | 0 | 6 | 2013-02-15 | |primus/emits| 0 | 0 | 13 | 2014-10-06 | |radubrehar/zemitter| 0 | 0 | 11 | 2014-09-08 | |redrockethq/jetpack| 0 | 0 | 4 | 2014-04-04 | |renra/event_emitter_js| 0 | 0 | 1 | 2014-03-13 | |reu/event-emitter.js| 0 | 0 | 4 | 2013-06-17 | |richRemer/scoped-event-emitter| 0 | 0 | 4 | 2014-09-01 | |roderickObrist/event-emitter| 0 | 0 | 1 | 2014-03-19 | |rpstewart/EventEmitter| 0 | 0 | 8 | 2012-11-06 | |sergeyt/fogbus.io| 0 | 0 | 23 | 2014-07-16 | |shiroyasha/Shiro-EventEmitter| 0 | 0 | 7 | 2013-05-10 | |skerit/hawkevents| 0 | 0 | 2 | 2014-06-18 | |sosnowski/event-emitter-ng| 0 | 0 | 8 | 2013-02-11 | |stayradiated/signals| 0 | 0 | 32 | 2014-03-23 | |supershabam/pevents| 0 | 0 | 29 | 2013-12-04 | |thechriswalker/TriggerHappy| 0 | 0 | 1 | 2012-09-28 | |theotheu/eventEmitter| 0 | 0 | 1 | 2014-09-16 | |thiagoneves/event-emitter| 0 | 0 | 3 | 2014-07-22 | |thomaswelton/bower-event-emitter| 0 | 0 | 16 | 2013-10-24 | |tim-smart/node-superemitter| 0 | 0 | 6 | 2014-06-19 | |tomasperezv/event-emitter| 0 | 0 | 2 | 2013-10-20 | |tunderdomb/EventStation| 0 | 0 | 2 | 2014-06-16 | |tvsudhir/EventEmitter| 0 | 0 | 11 | 2014-07-30 | |yomotsu/PeriodicEventEmitter| 0 | 0 | 1 | 2014-08-11 | |zaphod1984/eventEmitterDemux| 0 | 0 | 8 | 2014-02-19 |