Package Exports

nanoevents

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (nanoevents) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Nano Events

Small and simple events API.

No node.js EventEmitter compatibility.
Only 447 bytes (minified and gzipped).
on and once methods return unbind function. You don’t need to save callback to variable for removeListener.
No aliases, just emit, on, once methods.

import NanoEvents from 'nanoevents'
const emitter = new NanoEvents()

const unbind = emitter.on('tick', volume => {
  summary += volume
})
emitter.once('tick', () => {
  works = true
})

function disable () {
  unbind()
}

Usage

Mixing to Object

Because main Nano Events API has only 2 methods, you could just create proxy methods in your class:

class Ticker {
  constructor() {
    this.emitter = new NanoEvents()
  }
  on() {
    return this.emitter.on.apply(this.events, arguments)
  }
  once() {
    return this.emitter.once.apply(this.events, arguments)
  }
  tick() {
    this.emitter.emit('tick')
  }
}

Add Listener

There are 2 methods to add listener for specific event: on and one-time once.

emitter.on('tick', number => {
  console.log('on ' + number)
})
emitter.once('tick', number => {
  console.log('once ' + number)
})

emitter.emit('tick', 1)
// Prints "on 1" and "once 1"
emitter.emit('tick', 2)
// Prints "on 2"

Remove Listener

Methods on and once return unbind function. Call it and this listener will be removed from event.

const unbind = emitter.on('tick', number => {
  console.log('on ' + number)
})

emitter.emit('tick', 1)
// Prints "on 1"

unbind()
emitter.emit('tick', 2)
// Prints nothing

Execute Listeners

Method emit will execute all listeners. First argument is event name, others will be passed to listeners.

emitter.on('tick', (a, b) => {
  console.log(a, b)
})
emitter.emit('tick', 1, 'one')
// Prints 1, 'one'

Events List

You can get used events list by events property.

const unbind = emitter.on('tick', () => { })
Object.keys(emitter.events) //=> ["tick"]

unbind()
Object.keys(emitter.events) //=> []