@librpc/ee

Event Emitter

Modern event emitter

Table of Contents

• Features
• Install
• Usage
• API
• Benchmark
• Development

Features

• Simple 87 LOC
• Lightweight 522 bytes
• Performant
• Inheritable

Install

npm install --save @librpc/ee

or download dev or prod version

Usage

import EventEmitter from '@librpc/ee'

var emitter = new EventEmitter()

function listener (data) {
  console.log(data)
}

emitter.on('event', listener)
emitter.emit('event', { foo: 'bar' }) // -> { foo: 'bar' } in console
emitter.off('event', listener)

API

Emitter

• new Emitter()
• .on(event, listener) ⇒ Emitter
• .off(event, listener) ⇒ Emitter
• .emit(event, data) ⇒ Emitter

new Emitter()

Create an event emitter

Example

var emitter = new Emitter()

emitter.on(event, listener) ⇒ Emitter

Add listener to event. No context provided, use Function.prototype.bind(), arrow function or closure instead.

Kind: instance method of Emitter Returns: Emitter - Return self

Param	Type	Description
event	string	Event name
listener	listener	Event listener

Example

function listener (data) {
 console.log(data)
}

emitter.on('event', listener)

emitter.off(event, listener) ⇒ Emitter

Remove listener from event.

Kind: instance method of Emitter Returns: Emitter - Return self

Param	Type	Description
event	string	Event name
listener	listener	Event listener

Example

emitter.off('event', listener)

emitter.emit(event, data) ⇒ Emitter

Trigger an event. Multiple arguments not supported, use destructuring instead.

Kind: instance method of Emitter Returns: Emitter - Return self

Param	Type	Description
event	string	Event name
data	*	Event data

Example

emitter.emit('event', { foo: 'bar' })

listener : function

Param	Type	Description
data	*	Any data could be passed to event listener

Benchmark

> @librpc/ee@1.0.5 bench D:\Projects\event-emitter
> node bench/

┌──────────────────────────────┬─────────┬───────────┬─────────┐
│ EMITTER                      │ ON      │ EMIT      │ OFF     │
├──────────────────────────────┼─────────┼───────────┼─────────┤
│ events                       │ 99,258  │ 2,147,706 │ 187,842 │
├──────────────────────────────┼─────────┼───────────┼─────────┤
│ minivents                    │ 39,103  │ 1,737,633 │ 11,219  │
├──────────────────────────────┼─────────┼───────────┼─────────┤
│ mitt                         │ 134,112 │ 1,792,035 │ 231,187 │
├──────────────────────────────┼─────────┼───────────┼─────────┤
│ eventemitter3                │ 31,669  │ 2,188,591 │ 16,539  │
├──────────────────────────────┼─────────┼───────────┼─────────┤
│ ../dist/event-emitter.umd.js │ 142,386 │ 2,231,370 │ 269,298 │
└──────────────────────────────┴─────────┴───────────┴─────────┘

Development

Command	Description
npm run check	Check standard code style by snazzy
npm run build	Wrap source code in UMD by rollup
npm run bench	Run benchmark
npm run test	Run tests by tape and compute code coverage by nyc
npm run min	Minify code by UglifyJS
npm run docs	Create docs by jsdoc-to-markdown