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event-pubsub
Advanced tools
Super light and fast Extensible PubSub events and EventEmitters for Node and the browser with support for ES6 by default, and ES5 versions for older verions of node and older IE/Safari versions. Easy for any developer level. No frills, just high speed pub
The event-pubsub package is a Node.js module that provides a simple interface for implementing the publish-subscribe pattern. This pattern allows for the creation of a decoupled system where publishers and subscribers can communicate through events without being directly connected.
Event Emission
This feature allows you to emit events with a specified name and pass data to the event listeners. In the code sample, an event listener is set up to listen for the 'sayHello' event and emit that event with a parameter.
const EventPubSub = require('event-pubsub');
const events = new EventPubSub();
// Event listener
events.on('sayHello', name => console.log(`Hello, ${name}!`));
// Emit event
events.emit('sayHello', 'World');
Event Listening
This feature allows you to listen for events by name. When the event is emitted, the callback function is called with any data passed to the event. In the code sample, an event listener is set up to listen for the 'dataReceived' event.
const EventPubSub = require('event-pubsub');
const events = new EventPubSub();
// Event listener
events.on('dataReceived', data => console.log(`Data: ${data}`));
Once Listeners
This feature allows you to set up event listeners that will only be triggered once. After the event is emitted and the listener is invoked, the listener is removed. In the code sample, an event listener is set up to listen for the 'initialize' event and will only be triggered once.
const EventPubSub = require('event-pubsub');
const events = new EventPubSub();
// Event listener that fires once
events.once('initialize', () => console.log('Initialization complete.'));
Removing Listeners
This feature allows you to remove specific event listeners. In the code sample, an event listener is added and then removed for the 'message' event.
const EventPubSub = require('event-pubsub');
const events = new EventPubSub();
function onMessage(content) {
console.log(`Message: ${content}`);
}
// Add and remove an event listener
events.on('message', onMessage);
events.off('message', onMessage);
eventemitter3 is a high performance EventEmitter. It provides similar functionality to event-pubsub but focuses on performance and is compatible with different module systems (CommonJS, AMD, and browser globals).
mitt is a tiny functional event emitter / pubsub. It offers a similar publish-subscribe pattern but with a smaller footprint, making it a good choice for front-end development and projects where size is a concern.
wolfy87-eventemitter is an EventEmitter implementation that provides asynchronous event emitting and namespaced events. It is more feature-rich compared to event-pubsub, offering additional functionality such as context binding and wildcard events.
npm info :
GitHub info :
Super light and fast Extensible PubSub events and EventEmitters for Node and the browser with support for ES6 by default, and ES5 versions for older verions of node and older IE/Safari versions.
For older versions of node and io.js the latest versions of event-pubsub
may work with the --harmony flag. Officially though, we support node v4 and newer with es5 and es6
Easy for any developer level. No frills, just high speed events following the publisher subscriber pattern!
See NPM stats for event-pubsub
EXAMPLE FILES
Node Install
npm i --save event-pubsub
By default the correct version (ES5/ES6) will be included. You can force the es5/6 version by requiring event-pubsub/es5
or event-pubsub/es6
.
Browser Install
see browser examples above or below
<script src='path/to/event-pubsub-browser.js'></script>
<!-- OR ES5 for older browser support
<script src='path/to/event-pubsub-browser-es5.js'></script>
-->
Method | Arguments | Description |
---|---|---|
subscribe | type (string), handler(function), once (bool/optional) | will bind the handler function to the the type event. Just like addEventListener in the browser. If once is set to true the hander will be removed after being called once. |
on | same as above | same as above |
once | type (string), handler(function) | will bind the handler function to the the type event and unbind it after one execution. Just like addEventListener in the browser withe the once option set |
unSubscribe | type (string), handler(function or *) | will unbind the handler function from the the type event. If the handler is * , all handlers for the event type will be removed. Just like removeEventListener in the browser, but also can remove all event handlers for the type. |
off | same as above | same as above |
publish | type (string), ...data arguments | will call all handler functions bound to the event type and pass all ...data arguments to those handlers |
emit | same as above | same as above |
trigger | same as above | same as above |
While publish
, subscribe
, and unSubscribe
are the proper method names for the publisher/subscriber model, we have included on
, off
, and emit
as well because these are the most common event method names, and shorter. We have also kept the trigger
method as an alias for publish
and emit
for backwards compatability with earlier versions of event-pubsub
.
*
typeThe *
type is a special event type that will be triggered by any publish or emit the handlers for these should expect the first argument to be the type and all arguments after to be data arguments.
NOTE - the only difference between node and browser code is how the events
variable is created
const events = new Events
const events = new window.EventPubSub;
// ES5/ES6 now automatically chosen based on node version
const Events = new require('event-pubsub');
const events=new Events;
events.on(
'hello',
function(data){
console.log('hello event recieved ', data);
events.emit(
'world',
{
type:'myObject',
data:{
x:'YAY, Objects!'
}
}
)
}
);
events.on(
'world',
function(data){
console.log('World event got',data);
events.off('*','*');
console.log('Removed all events');
}
);
events.emit(
'hello',
'world'
);
events.on(
'hello',
someFunction
).on(
'goodbye',
anotherFunction
).emit(
'hello',
'world'
);
events.emit(
'goodbye',
'complexity'
).off(
'hello',
'*'
);
<!DOCTYPE html>
<html>
<head>
<title>PubSub Example</title>
<script src='../../event-pubsub-browser.js'></script>
<!-- OR ES5 for older browser support
<script src='../../event-pubsub-browser-es5.js'></script>
-->
<script src='yourAmazingCode.js'></script>
</head>
<body>
...
</body>
</html>
var events = new window.EventPubSub();
events.on(
'hello',
function(data){
console.log('hello event recieved ', data);
events.emit(
'world',
{
type:'myObject',
data:{
x:'YAY, Objects!'
}
}
)
}
);
events.emit(
'hello',
'world'
);
events.emit(
'hello',
'again','and again'
);
// ES5/ES6 now automatically chosen based on node version
const Events = require('event-pubsub');
// manually include es6
// const Events = require('event-pubsub/es6');
class Book extends Events{
constructor(){
super();
//now Book has .on, .off, and .emit
this.words=[];
}
add(...words){
this.words.push(...words);
this.emit(
'added',
...words
);
}
read(){
this.emit(
'reading'
);
console.log(this.words.join(' '));
}
}
const book=new Book;
book.on(
'added',
function(...words){
console.log('words added : ',words);
this.read();
}
);
book.add(
'once','upon','a','time','in','a','cubicle'
);
// manually include es5
const Events = require('event-pubsub/es5.js');
function Book(){
//extend happens below
Object.assign(this,new Events);
//now Book has .on, .off, and .emit
this.words=[];
this.add=add;
this.erase=erase;
this.read=read;
function add(){
arguments.slice=Array.prototype.slice;
this.words=this.words.concat(
arguments.slice()
);
this.emit(
'added',
arguments.slice()
);
}
function read(){
this.emit(
'reading'
);
console.log(this.words.join(' '));
}
return this;
};
const book=new Book;
book.on(
'added',
function(...words){
console.log('words added : ',words);
this.read();
}
);
book.add(
'once','upon','a','time','in','a','cubicle'
);
FAQs
Super light and fast Extensible ES6+ events and EventEmitters for Node and the browser. Easy for any developer level, use the same exact code in node and the browser. No frills, just high speed events!
The npm package event-pubsub receives a total of 907,548 weekly downloads. As such, event-pubsub popularity was classified as popular.
We found that event-pubsub demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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