This project uses node and npm. Go check them out if you don't have them locally installed.
$ npm install --save subscribe// using ES6 modules
import { Emitter } from 'subscribe'
// using CommonJS modules
var { Emitter } = require('subscribe')The UMD build is also available on unpkg:
<script src="https://esm.sh/subscribe"></script>You can find the library on window.__Emitter__.
import {Emitter} from 'subscribe'
// OR
const {Emitter} = require('subscribe')
const eventbus = new Emitter()
// listen to an event
eventbus.on('foo', e => console.log('foo', e) )
// listen to all events
// This will fire first the 'type' event if it exists
eventbus.on('*', (type, e) => console.log(type, e) )
// fire an event
eventbus.emit('foo', { a: 'b' })
// working with handler references:
function onFoo() {}
eventbus.on('foo', onFoo) // listen
eventbus.off('foo', onFoo) // unlisten
// remove all listeners for specific event
eventbus.off('foo')
// Fire event listener only once
eventbus.once('knock knock', (data) => console.log("I will be fired only once"))
eventbus.emit('knock knock', null)
// This will not fire
eventbus.emit('knock knock', null)For better autocompletion Emitter class takes parameters for possible event names :
import {Emitter} from 'subscribe'
const emitter = new Emitter<'foo' | 'bar'>()
emitter.on('foo', e => console.log('foo', e) )
emitter.on('bar', e => console.log('foo', e) )
// Will throw an error: (on typescript typecheck NOT ON RUNTIME!)
emitter.on('bar2', e => console.log('foo', e) )Use the constructor to initiate the eventbus with handlers
- ``
listenersEventHandlerMap
Register an event handler for the given type.
typeString Type of event to listen for, or"*"for all eventshandlerFunction Function to call in response to given event
Remove an event handler for the given type.
typeString Type of event to unregisterhandlerfrom, or"*"handlerFunction Handler function to remove
Invoke this.listeners handlers for the given type.
If present, "*" handlers are invoked after type-matched handlers.
Note: Manually firing "*" handlers is not supported.
typeString The event type to invokeevtAny? Any value (object is recommended and powerful), passed to each handler
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