Better Event Emitter

BetterEventEmitter is a custom event emitter with types and more functions.

Installation

npm i better-event-emitter

Usage

Typing the emitter

Typing using Generics

import { BetterEventEmitter } from 'better-event-emitter';

type EmitterType = {
    login: (username: string, password: string) => void,
    logout: (username: string) => void,
}

const emitter = new BetterEventEmitter<EmitterType>();

Typing using constructor

import { BetterEventEmitter } from 'better-event-emitter';

const emitter = new BetterEventEmitter({
    login: (username: string, password: string) => {},
    logout: (username: string) => {},
});

Register event listeners

on method

You can register a regular event listener using the on method. This listener will be called every time the specified event is emitted:

emitter.on('eventName1', (arg1, arg2) => {
  // Your event handler logic here
  console.log(`Event "eventName1" emitted with arguments: ${arg1}, ${arg2}`);
});

once method

You can register a one-time event listener using the once method. This listener will be called only once for the specified event:

emitter.once('eventName2', () => {
  // Your event handler logic here
  console.log('This listener will be called once when "eventName2" is emitted.');
});

onAny method

You can register an event listener for every event using the onAny method. This listener will be called for every emitted event:

emitter.onAny((event, ...args) => {
  // Your event handler logic here
  console.log(`Event ${event} emitted with arguments: ${arg1}, ${arg2}`);
});

Emit events

emit method

You can emit events using the emit method. Pass the event name and any required arguments:

emitter.emit('eventName1', 'Hello', 42);
emitter.emit('eventName2');

Remove event listeners

removeListener method

You can remove a specific event listener using the removeListener method. Provide the event name and the callback function:

const eventHandler = (arg1: string, arg2: number) => {
  // Your event handler logic here
};
emitter.on('eventName1', eventHandler);

// Later, remove the event listener
emitter.removeListener('eventName1', eventHandler);

removeGlobalListener method

You can remove a global event listener (registered using onAny) using the removeGlobalListener method. Provide the callback function:

const globalEventHandler = (event: keyof typeof emitter, ...args: any) => {
  // Your global event handler logic here
};
emitter.onAny(globalEventHandler);

// Later, remove the global event listener
emitter.removeGlobalListener(globalEventHandler);

Dispose the emitter

You can dispose the BetterEventEmitter instance to remove all event listeners:

emitter.dispose();

Example

import { BetterEventEmitter } from 'better-event-emitter';

type EmitterType = {
    login: (username: string, password: string) => void,
    logout: (username: string) => void,
}

const emitter = new BetterEventEmitter<EmitterType>();

emitter.on('login', (username, password) => {
    console.log(`${username} has logged in`);
});

emitter.on('logout', (username) => {
    console.log(`${username} has logged out`);
});