Act

:zap: Compact event emitter for browser (and server), with all necessary features. If you need tiny and not overloaded event system, you are in the right place. :checkered_flag: :wink:

• Compact -> Tiny size (~500 bytes)
• Full -> All Node's EventEmitter capabilities
• Universal -> Browser and server compatible
• Support -> IE 9+

How to Install

Install, using NPM:

$ npm install act.js --save

Include

As Node.js/Webpack/Browserify module:

// ES6 modules
import Act from 'act.js'

// CommonJS modules
const Act = require('act.js')

In browser:

<script src="https://unpkg.com/act.js/dist/act.min.js"></script>

How to Use

Just call it:

const act = Act()

Or use with class/objects (composition):

const myObject = {
    myFunction: function() {},
    emitter: Act()
}

API methods

After you have created event emitter object, this methods become available:

Properties

events

Returns a copy of the events object.

act.events // { eventName: [ [Function], [Function] ] }

Methods

on(event, handler, prepend)

Add handler to event or all events, executed when this event(events) is fired. The third argument says that the handler must be prepended to the handlers array.

act.on('data', () => {})

// add handler to the beginning of the array
act.on('data', () => {}, true)

// subscribe handler for all events
act.on('*', () => {})

once(event, handler, prepend)

Add handler to event, which can be called only once. You can also use * event type and prepend argument in once method.

act.once('data', () => {})

off(event[,handler])

Remove handler from event, event or all events.

// Handler for 'message' event
const show = () => {}
act.on('data', show)

// remove handler
act.off('data', show) 

// remove event with all handlers
act.off('data') 

// remove all events
act.off() 

fire(event[,arguments])

Emit event with arguments.

act.fire('data', 34, 'Jason')

Example

import Act from 'act.js'

const act = Act();

act.on('data', (data) => console.log('Next:', ++data.num))
act.on('notification', (name, msg) => console.log(name, ':', msg));
act.once('*', () => console.log('Called for all events.'));

console.log(act.events);

act.fire('data', { num: 11 });
act.fire('notification', 'Jason', 'Hello!');

// Otput:
// $ { data: [ [Function] ], notification: [ [Function] ], '*': [ { [Function] _once: true } ] }
// $ Next: 12
// $ Called for all events.
// $ Jason : Hello!

Compliance with the Node`s EE

emitter.on(eventName, listener) -> act.on(eventName, listener)

emitter.emit(eventName, args) -> act.fire(eventName, args)

emitter.eventNames() -> Object.keys(act.events)

emitter.listenerCount(eventName) -> act.events[eventName].length

emitter.listeners(eventName) -> act.events[eventName]

emitter.once(eventName, listener) -> act.once(eventName, listener)

emitter.prependListener(eventName, listener) -> act.on(eventName, listener, true)

emitter.prependOnceListener(eventName, listener) -> act.once(eventName, listener, true)

emitter.removeAllListeners() -> act.off()

emitter.removeAllListeners(eventName) -> act.off(eventName) // Removes event listeners.

emitter.removeListener(eventName, listener) -> act.off(eventName, listener)

License

MIT. © 2017 Taras Batenkov