light-event-bus
v1.0.1
Published
Lightweight event bus for node and the browser.
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light-event-bus.js
light-event-bus.js is a lightweight event bus for Node.js and the browser.
Table of Contents
Usage
This library can be used both with Node.js and the browser.
Browser usage
Download - browser
You can download the library here. For the browser there are 2 options:
- Download
light-event-bus.min.js
here and import it in your app using the<script>
tag. - If you are using ES modules, download the library (here or through NPM) and import it using ES6 imports.
This file is also delivered through a CDN at this address.
Example - browser
- Importing with
<script>
tag
<script src='../build/light-event-bus.min.js'></script>
<script>
const eventBus = new EVENT_BUS.EventBus()
const subscription = eventBus.subscribe('event', arg => console.log(arg))
eventBus.publish('event', 'message')
subscription.unsubscribe()
</script>
- Importing ES module
<script type='module'>
import { EventBus } from 'light-event-bus'
const eventBus = new EventBus()
const subscription = eventBus.subscribe('event', arg => console.log(arg))
eventBus.publish('event', 'message')
subscription.unsubscribe()
</script>
Node.js usage
Download - node
Run
npm install light-event-bus
or
yarn add light-event-bus
Example - node
const { EventBus } = require('light-event-bus')
const eventBus = new EventBus()
const subscription = eventBus.subscribe('event', arg => console.log(arg))
eventBus.publish('event', 'message')
subscription.unsubscribe()
API documentation
Table of Contents
EventBus
The EventBus
constructor can be accessed through the main object exposed by this library.
If you are using Node.js:
const { EventBus } = require('light-event-bus')
If you are using ES6 imports:
import { EventBus } from 'light-event-bus'
If you are using <script>
:
const eventBus = new EVENT_BUS.EventBus()
Subscribe
Instances of EventBus
expose a subscribe
method.
Call subscribe
when you want to start listening for an event.
subscribe
takes two arguments: eventType
and callback
.
Example:
eventBus.subscribe('event', arg => console.log(arg))
eventType
can be an object of any type. Strings are recomended.callback
must be a function. This function can have 0 or 1 argument.
Unsubscribe
subscribe
returns an object that exposes an unsubscribe
method.
Call unsubscribe
to cancel the current subscription.
Example:
const subscription = eventBus.subscribe('event', arg => console.log(arg))
// To cancel the subscription
subscription.unsubscribe()
Publish
Instances of EventBus
expose a publish
method.
Call publish
when you want to publish an event on the event bus.
publish
takes two arguments: eventType
and argument
.
Example:
eventBus.publish('event', 'message')
eventType
can be an object of any type. Strings are recomended.argument
is optional. It will be passed to all the listeners for the event. It can be of any type.
In the case of this examples, only subscribers of the event 'event'
will be called, with the string 'mesage'
as argument.
EventBusSingleton
Often a single instance of EventBus
is needed across an entire application, a singleton. The main object of this library already exposes a singleton, so that you don't have to create your own.
You can access the EventBusSingleton
in the following ways:
If you are using Node.js:
const { EventBusSingleton } = require('light-event-bus')
If you are using ES6 imports:
import { EventBusSingleton } from 'light-event-bus'
If you are using <script>
:
const eventBus = new EVENT_BUS.EventBusSingleton()
This singleton is just an instance of EventBus
, so it can be used as any other user-defined EventBus
.