emit-listenner

emit-listenner

emit-listenner is a slim EventEmitter implementation based on ESM.

NOTE: Please ensure your nodejs version is great than 12.17!

Install

npm install --save emit-listenner

Usage

Normal usage

// foo.js
import emitListenner from 'emit-listenner'
const event = new emitListenner.EventEmitter()
event.addListenner("eventname", callback);        // register a listenner
event.emit("eventname", {
    a: 'some args'
});  // emit event

emit-listenner is a module based on ES-module, if you want use it in Nodejs with CommonJS pattern, you can use dynamic import expression that is a nodejs new feature that used to import ES module in Commonjs module. But if you do this, make sure your nodejs version is great than v12.13!

// foo.cjs
(async ()=>{
    const { EventEmitter } = await import('emit-listenner')
    const ev = new EventEmitter()
    ev.addListenners([
        {
            name: "change",
            handler: args=>console.log(args),
            once: true
        }
    ])
})

Documentation

EventEmitter class

EventEmitter#addListenner(name, handler)

Register a listenner for certain specified event, when event trigged them will be called orderly.

EventEmitter#addListenners(events)

Register multiple events at once. the events is an array of structure like below:

{
    name: string;           // event name
    handler: args=>any;     // it will be called when event is triggered
    once?: boolean;         // same as `EventEmitter#once`, default false
}

EventEmitter#off(name, handler?)

Alias of EventEmitter#removeListenner

EventEmitter#on(name, handler)

Alias of EventEmitter#addListenner

EventEmitter#once(name, handler)

Register a listenner for certain specified event, but just only effects one time.

Note: Register a same event continuously for the same time, and the latter will overwrite the former

EventEmitter#removeListenner(name, handler?)

Remove specified listenner for the specified event, but will remove all listenners of name event when handler is not set.

EventEmitter#removeAllListenners()

Remove all registered events and its listenners.

EventEmitter#hasListenner(name, handler)

EventEmitter#listennerCount(name)

Get count of listenners of specified event.

EventEmitter#emit(name, args)

Emit a event with optional arguments.

EventEmitter#trigger(name, args)

alias of EventEmitter#emit.

License

MIT.