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+.

Table of Contents

• Install
• Usage
• Examples & Demos
• API
• Contribute
• License

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

Preact + Mitt Codepen Demo

---

API

emitt

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

Parameters

• all EventHandlerMap

Returns Emitt

on

Register an event handler for the given type.

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

• ...args [any[]] rest arguments for event

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.

Submitting pull requests

Pull requests are the greatest contributions, so be sure they are focused in scope, and do avoid unrelated commits.

• Fork it!
• Clone your fork: git clone https://github.com/<your-username>/emitt
• Navigate to the newly cloned directory: cd emitt
• Create a new branch for the new feature: git checkout -b my-new-feature
• Install the tools necessary for development: npm install
• Make your changes.
• Commit your changes: git commit -am 'Add some feature'
• Push to the branch: git push origin my-new-feature
• Submit a pull request with full remarks documenting your changes.

License

MIT License © Jason Miller, Andrey Rublev