Emitt NPM | npm.io

Emitt is Extended mitt

Differencies from mitt

Main difference is that you can emit as many arguments as you want:

emitter.emit('event', 'b', 1, ['arg1', 'foo', 'bar'])

Tiny 224b functional event emitter / pubsub.

Microscopic: weighs less than 225 bytes gzipped
Useful: a wildcard "*" event type listens to all events
Familiar: same names & ideas as Node's EventEmitter
Functional: methods don't rely on this, also you can pass as many as you want event arguments to emit method
Great Name: somehow emitt wasn't taken

EMitt was made for the browser, but works in any JavaScript runtime. It has no dependencies and supports IE9+.

Install

This project uses node and npm. Go check them out if you don't have them locally installed.

$ npm install --save emitt

Then with a module bundler like rollup or webpack, use as you would anything else:

// using ES6 modules
import emitt from 'emitt'

// using CommonJS modules
var emitt = require('emitt')

The UMD build is also available on unpkg:

<script src="https://unpkg.com/emitt/dist/mitt.umd.js"></script>

You can find the library on window.emitt.

Usage

import emitt from 'emitt'

const emitter = emitt()

// listen to an event
emitter.on('foo', e => console.log('foo', e) )

// listen to all events
emitter.on('*', (type, e) => console.log(type, e) )

// fire an event
emitter.emit('foo', { a: 'b' })

// working with handler references:
function onFoo() {}
emitter.on('foo', onFoo)   // listen
emitter.off('foo', onFoo)  // unlisten

Typescript

import emitt from 'emitt';
const emitter: mitt.Emitter = emitt();

Examples & Demos

API

emitt

EMitt: Tiny (~225b) functional event emitter / pubsub.

Parameters

all EventHandlerMap

Returns Emitt

on

Parameters

type String Type of event to listen for, or "*" for all events
handler Function Function to call in response to given event

off

Remove an event handler for the given type.

Parameters

type String Type of event to unregister handler from, or "*"
handler Function Handler function to remove

emit

Invoke all handlers for the given type. If present, "*" handlers are invoked after type-matched handlers.

Parameters

type String The event type to invoke

Contribute

First off, thanks for taking the time to contribute! Now, take a moment to be sure your contributions make sense to everyone else.

Development Start:

This project is typed with Flow Type annotations. To ensure you have the proper typings for this project run

flow-typed install

Reporting Issues

Found a problem? Want a new feature? First of all see if your issue or idea has already been reported. If don't, just open a new clear and descriptive issue.