Simple event bus

A simple, no-dependency, synchronous event bus written in TypeScript

# NPM
npm i --save @sylvmty/simple-event-bus
# PNPM
pnpm add --save @sylvmty/simple-event-bus
# Yarn
yarn add @sylvmty/simple-event-bus

Features

• Native TypeScript support
• No dependencies
• Synchronous event bus
• Event handlers with priority (sorted execution)
• Easy to use
• Lightweight: 0.88 kB (0.39 kB with gzip)
• Compiled in ESM, CJS, UMD for convenience
• NestJS native package

Motivations

I decided to create my own library after using EventEmitter2 for some time in my projects.

I found it too complex for my needs and it was also lacking some features like prioritized event handlers.

Documentations

Example

import { EventBus } from "@sylvmty/simple-event-bus"

const eventBus = new EventBus()

eventBus.on("myEvent", (message: string, eventName: string) => {
  console.log("Handler 1:", message, `(event name: ${eventName})`)
})
// Also works with async handlers (they will still be executed sequentially)
eventBus.on("myEvent", async (message: string, eventName: string) => {
  console.log("Handler 2:", message, `(event name: ${eventName})`)
})

await await eventBus.emit("myEvent", "This is a message")

// Output:
// Handler 1: This is a message (event name: myEvent)
// Handler 2: This is a message (event name: myEvent)

Native TypeScript package documentation

NestJS package documentation

Contribute

If you have an idea for an improvement, feel free to fork this repository and submit a PR!

Requirements

• Node.js LTS (you can use nvm to manage Node versions)
• pnpm (npm install -g pnpm)

Install dependencies

pnpm install

Scripts

The template contains the following pnpm scripts:

• dev - Start the file watcher (will recompile the code on source file change)
• build - Build for production
• lint - Checks your code for any linting errors
• test - Run all tests
• test:watch - Run all tests with watch mode
• test:coverage - Run all tests with code coverage report

License

This repository under the MIT License, feel free to use it and modify it.