EventEmitter in JavaScript
Synopsis
EventEmitter is an implementation of the Event-based architecture in JavaScript.
The code is written using the ES2015 approaches, including creation of private property through WeakMap that allows you to not to check for clearing memory, and let it do to the garbage collector.
The module contains the most basic and necessary things: subscription to an event, unsubscribing from the events, running event only once, setting the maximum number of listeners.
The focus is on code readability, speed of execution, getting rid of all the excess.
You can use this library in browser either at the server as within the node.js.
Installation
npm i --save es-event-emitter
or
git clone https://github.com/Zlobin/es-event-emitter.git
cd es-event-emitter && npm i && webpack
Benchmark
Run npm start
.
const EM = ; EM ;
// Manual:
es-event-emitter 100,000: 29284943 nanoseconds
Node.js native 100,000: 41954981 nanoseconds
EventEmitter2 100,000: 91033365 nanoseconds
event-emitter 100,000: 211658201 nanoseconds
// Via benchmark library:
es-event-emitter x 21,508,327 ops/sec ±0.47% (76 runs sampled)
event-emitter x 5,444,296 ops/sec ±0.40% (89 runs sampled)
EventEmitter2 x 18,105,022 ops/sec ±2.07% (74 runs sampled)
Node.js native x 17,800,136 ops/sec ±0.87% (83 runs sampled)
Fastest is es-event-emitter
Dependencies
There are no dependencies. You need only npm installed and just run npm i
to grab the development dependencies.
Examples
var EM = ;
html inculde:
Or ES2015 import:
;// ...
Creating an instance.
var EM = ;
An usual example.
EM; EM;
It will be triggered only once and then callbacks will be removed.
EM; EM;// Nothing happend.EM;
Callback with parameters.
EM; EM;
Callback's call can be ordered by "weight" parameter.
EM; EM; EM; EM;// 3// 2// 1
Chaining.
EM; EM ;
Set maxNumberOfListeners as a parameter when creating new instance.
const EM = 1; EM;// Note: it will show notification in console.EM;
Testing
Tests are performed using mocha and expect library npm test
.
Building the documentation
You can use JSDoc comments found within the source code.
Todo
- Add event's namespace:
EM;
- Add events through comma:
EM;
- Add method "onAny" for listening each event:
EM;