Beyond Node.js: Exploring Deno and Other Alternatives

Sep 25, 2020•5 min read

As the JavaScript ecosystem evolves, new runtime environments are emerging to address Node.js's limitations. Let's explore Deno and other alternatives.

Deno: The Modern Runtime

Deno is a secure runtime for JavaScript and TypeScript, created by Node.js's original creator.

Basic Server Example

typescript
// server.ts
import { serve } from "https://deno.land/std/http/server.ts";

const server = serve({ port: 8000 });
console.log("Server running on http://localhost:8000/");

for await (const req of server) {
  req.respond({ body: "Hello from Deno!" });
}

Security Features

typescript
// Explicit permissions required
const file = await Deno.open("example.txt", {
  read: true,
  write: true,
});

// Network access needs permission
const response = await fetch("https://api.example.com", {
  headers: {
    "Authorization": Deno.env.get("API_KEY") // Requires --allow-env
  }
});

Bun: Performance Focused

Bun is a fast all-in-one JavaScript runtime and toolkit.

HTTP Server

javascript
// server.js
export default {
  port: 3000,
  fetch(request) {
    return new Response("Hello from Bun!");
  },
};

// Start with: bun run server.js

File Operations

javascript
// Fast file operations
const file = await Bun.file("large.txt");
const text = await file.text();

// Write file
await Bun.write("output.txt", "Hello, Bun!");

Fresh: The Edge Framework

Fresh is a next-generation web framework for Deno.

Route Handler

typescript
// routes/api/data.ts
import { HandlerContext } from "$fresh/server.ts";

export const handler = async (
  req: Request,
  _ctx: HandlerContext
): Promise<Response> => {
  const data = {
    message: "Hello from Fresh!",
    timestamp: new Date().toISOString(),
  };
  
  return new Response(JSON.stringify(data), {
    headers: { "Content-Type": "application/json" },
  });
};

Component

tsx
// components/Counter.tsx
import { useState } from "preact/hooks";

export default function Counter() {
  const [count, setCount] = useState(0);
  
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>
        Increment
      </button>
    </div>
  );
}

Oak: Deno's Express

Oak is a middleware framework for Deno's HTTP server.

Middleware Example

typescript
import { Application, Router } from "https://deno.land/x/oak/mod.ts";

const app = new Application();
const router = new Router();

// Logger middleware
app.use(async (ctx, next) => {
  const start = Date.now();
  await next();
  const ms = Date.now() - start;
  console.log(`${ctx.request.method} ${ctx.request.url} - ${ms}ms`);
});

router.get("/", (ctx) => {
  ctx.response.body = "Hello from Oak!";
});

app.use(router.routes());
app.use(router.allowedMethods());

await app.listen({ port: 8000 });

Performance Comparisons

HTTP Benchmark

typescript
// benchmark.ts
const results = {
  "node": {
    "requests/sec": 12000,
    "latency": "1.2ms",
    "memory": "60MB"
  },
  "deno": {
    "requests/sec": 15000,
    "latency": "0.9ms",
    "memory": "45MB"
  },
  "bun": {
    "requests/sec": 18000,
    "latency": "0.7ms",
    "memory": "35MB"
  }
};

Security Features

Deno's Permissions

typescript
// Explicit permissions model
{
  "permissions": {
    "net": ["localhost:8000"],
    "read": ["./data"],
    "write": ["./logs"],
    "env": ["API_KEY"],
    "run": ["deno", "npm"]
  }
}

Runtime Security

typescript
// Secure by default
import { serve } from "https://deno.land/std/http/server.ts";

const server = serve({ 
  port: 8000,
  hostname: "0.0.0.0",
  cert: await Deno.readFile("./cert.pem"),
  key: await Deno.readFile("./key.pem")
});

Module Systems

ESM in Deno

typescript
// Direct URL imports
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
import { serve } from "https://deno.land/std/http/server.ts";

// Local modules
import { Database } from "./db.ts";

Package Management

json
// Node.js (package.json)
{
  "dependencies": {
    "express": "^4.17.1",
    "typescript": "^4.3.5"
  }
}

// Deno (deps.ts)
export {
  serve } from "https://deno.land/std@0.140.0/http/server.ts";
export {
  assertEquals
} from "https://deno.land/std@0.140.0/testing/asserts.ts";

Testing and Development

Deno Testing

typescript
// test.ts
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";

Deno.test("basic test", () => {
  const result = 2 + 2;
  assertEquals(result, 4);
});

// Run with: deno test

Development Tools

typescript
// Watch mode
const watcher = Deno.watchFs("./src");
for await (const event of watcher) {
  console.log(">>>> event", event);
  // Trigger reload or rebuild
}

Deployment Options

Docker Setup

dockerfile
# Deno Dockerfile
FROM denoland/deno:1.24.3

WORKDIR /app
COPY . .

RUN deno cache main.ts

EXPOSE 8000
CMD ["deno", "run", "--allow-net", "main.ts"]

Cloud Deployment

yaml
# deno.deploy.json
{
  "project": "my-deno-app",
  "entrypoint": "main.ts",
  "env": {
    "DATABASE_URL": "${{ secrets.DATABASE_URL }}"
  },
  "regions": ["us-east1", "europe-west1"]
}

Migration Strategies

From Node.js to Deno

typescript
// Node.js
const express = require('express');
const app = express();

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

app.listen(3000);

// Deno equivalent
import { Application } from "https://deno.land/x/oak/mod.ts";
const app = new Application();

app.use((ctx) => {
  ctx.response.body = "Hello World";
});

await app.listen({ port: 3000 });

Conclusion

Key Takeaways:

  • Deno offers better security
  • Bun focuses on performance
  • Modern module systems
  • Built-in TypeScript support
  • Better developer experience

When to Choose Each:

  • Deno: Security-critical applications
  • Bun: Performance-critical systems
  • Node.js: Legacy system compatibility
  • Fresh: Modern web applications
  • Oak: API development

Consider:

  • Project requirements
  • Team expertise
  • Ecosystem maturity
  • Performance needs
  • Security requirements

For more information: