Introduction

In the ever-evolving landscape of JavaScript runtimes, developers are presented with multiple options for server-side development. This blog post aims to compare three popular runtimes: Node.js, Deno 2.0, and Bun, to help you make an informed decision about which one might be best for your projects. Each of these runtimes offers unique features and capabilities, catering to different development needs and preferences.

What are Node.js, Deno 2.0, and Bun?

Node.js is a long-standing JavaScript runtime built on Chrome's V8 JavaScript engine¹. It was first released in 2009 and has since become the de facto standard for server-side JavaScript development. Node.js allows developers to use JavaScript for both frontend and backend development, creating a unified language environment across the full stack.

Deno 2.0 is a secure runtime for JavaScript and TypeScript, created by Ryan Dahl, the original developer of Node.js. Launched in 2018, Deno aims to address some of the design flaws in Node.js while providing enhanced security features and native TypeScript support. It's built on the V8 JavaScript engine, the Rust programming language, and Tokio, an asynchronous runtime for Rust².

Bun is a newcomer in the JavaScript runtime scene, designed as an all-in-one JavaScript runtime and toolkit with a focus on speed and developer experience. Released in 2022, Bun is built on the JavaScriptCore engine (used in WebKit) and written in Zig, a low-level programming language³. It aims to provide a faster and more efficient alternative to existing JavaScript runtimes.

Feature Comparison

Security

• Node.js: Requires manual configuration for security. Developers need to implement security measures themselves, such as input validation, output encoding, and proper error handling. This flexibility allows for customized security implementations but can lead to vulnerabilities if not properly managed.

Example (Node.js):

const express = require('express')
const app = express()

app.use((req, res, next) => {
  // Custom security middleware
  if (req.headers['x-auth-token'] !== 'secret') {
    return res.status(403).send('Unauthorized')
  }
  next()
})

app.get('/', (req, res) => {
  res.send('Secure route')
})

app.listen(3000, () => console.log('Server running on port 3000'))

• Deno 2.0: Built-in security features with a permissions system. Deno runs code in a sandbox environment by default and requires explicit permissions for file system access, network access, and other sensitive operations. This approach significantly reduces the risk of malicious code execution.

Example (Deno):

// Run with: deno run --allow-net server.ts

import { serve } from 'https://deno.land/std@0.140.0/http/server.ts'

const handler = (req: Request): Response => {
  return new Response('Hello from Deno!')
}

console.log('Listening on http://localhost:8000')
await serve(handler, { port: 8000 })

• Bun: Follows Node.js security model with some enhancements. While it doesn't have Deno's strict permissions system, Bun implements certain security features by default, such as buffer overflow protection and improved error messages for security-related issues.

Example (Bun):

const server = Bun.serve({
  port: 3000,
  fetch(req) {
    return new Response('Hello from Bun!')
  },
})

console.log(`Listening on http://localhost:${server.port}`)

TypeScript Support

• Node.js: Requires additional setup. Developers need to install TypeScript separately and configure their project to use it. This usually involves setting up a tsconfig.json file and using tools like ts-node for execution.

Example (Node.js with TypeScript):

// app.ts
import express from 'express'

const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('Hello, TypeScript!')
})

app.listen(port, () => {
  console.log(`Server running at http://localhost:${port}`)
})

// Run with: ts-node app.ts

• Deno 2.0: Native TypeScript support. Deno can execute TypeScript files directly without any additional configuration or compilation step. This seamless integration makes it easier for developers to adopt TypeScript in their projects.

Example (Deno):

// app.ts
import { serve } from 'https://deno.land/std@0.140.0/http/server.ts'

const handler = (req: Request): Response => {
  return new Response('Hello, TypeScript in Deno!')
}

console.log('TypeScript server running on http://localhost:8000')
await serve(handler, { port: 8000 })

// Run with: deno run --allow-net app.ts

• Bun: Native TypeScript support. Similar to Deno, Bun can run TypeScript files out of the box. It also includes its own TypeScript compiler, which is significantly faster than the official TypeScript compiler.

Example (Bun):

// app.ts
const server = Bun.serve({
  port: 3000,
  fetch(req: Request): Response {
    return new Response('Hello, TypeScript in Bun!')
  },
})

console.log(`TypeScript server running on http://localhost:${server.port}`)

// Run with: bun run app.ts

Package Management

• Node.js: Uses npm (Node Package Manager). npm is the world's largest software registry, with millions of packages available. It uses a package.json file to manage dependencies and project metadata.

Example (Node.js):

// package.json
{
  "name": "my-node-project",
  "version": "1.0.0",
  "dependencies": {
    "express": "^4.17.1"
  }
}

npm install
npm start

• Deno 2.0: URL-based imports, no package.json. Deno allows developers to import modules directly from URLs, eliminating the need for a centralized package registry. This approach promotes decentralization but can lead to versioning and caching challenges.

Example (Deno):

import { serve } from 'https://deno.land/std@0.140.0/http/server.ts'
import * as colors from 'https://deno.land/std@0.140.0/fmt/colors.ts'

// ... rest of the code

• Bun: Compatible with npm, but also has its own package manager. Bun can use existing npm packages and package.json files, ensuring compatibility with the vast npm ecosystem. Additionally, it provides its own package manager, which is significantly faster than npm and yarn.

Example (Bun):

// package.json
{
  "name": "my-bun-project",
  "version": "1.0.0",
  "dependencies": {
    "express": "^4.17.1"
  }
}

bun install
bun run start

Performance

• Node.js: Good performance, but slower startup times. Node.js has been optimized over the years and performs well for most applications. However, it can have slower startup times, especially for large applications with many dependencies.

Example (Node.js performance test):

console.time('operation')
// Perform some operation
console.timeEnd('operation')

• Deno 2.0: Improved performance over Node.js. Deno's use of Rust and its streamlined architecture result in better performance in many scenarios. It also has faster startup times compared to Node.js.

Example (Deno performance test):

const start = performance.now()
// Perform some operation
const end = performance.now()
console.log(`Operation took ${end - start} milliseconds`)

• Bun: Significantly faster startup and runtime performance. Bun is designed with performance as a primary goal. Its use of the JavaScriptCore engine and the Zig programming language results in extremely fast startup times and runtime performance, often outperforming both Node.js and Deno.

Example (Bun performance test):

const start = Bun.nanoseconds()
// Perform some operation
const end = Bun.nanoseconds()
console.log(`Operation took ${(end - start) / 1e6} milliseconds`)

Which is Better and Why?

The "best" runtime depends on your specific needs and use case. However, let's break it down in more detail:

1. For legacy projects and wide ecosystem support, Node.js remains a solid choice. Its mature ecosystem, extensive documentation, and vast community make it ideal for large-scale, production-ready applications. The abundance of libraries and tools in the npm registry can significantly speed up development.

2. If security and TypeScript are your primary concerns, Deno 2.0 shines. Its built-in security features and native TypeScript support make it an excellent choice for projects where security is paramount. Deno's modern approach to module imports and its standard library also appeal to developers looking for a more streamlined experience.

3. For maximum performance and developer experience, Bun takes the lead. Its blazing-fast startup times and runtime performance make it ideal for serverless functions and microservices where cold start times are critical. Bun's all-in-one approach, including a fast package manager and bundler, can significantly improve developer productivity.

Bun stands out as a promising option for new projects due to its superior performance, npm compatibility, and focus on developer experience. It combines the best features of Node.js and Deno while adding its own innovations. For example, its built-in SQLite support and hot reloading capabilities can simplify development workflows.

However, it's important to note that Bun is still relatively new and may lack some features or have stability issues compared to the more mature Node.js and Deno. Its ecosystem is still growing, and some npm packages may not be fully compatible.

In conclusion, while each runtime has its strengths, Bun appears to be pushing the boundaries of what's possible in JavaScript runtimes. Its performance benefits and developer-friendly features make it an exciting option for future projects, potentially becoming the preferred choice as it matures. However, the choice between Node.js, Deno, and Bun should ultimately be based on your project requirements, team expertise, and long-term maintenance considerations.