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arenasbob2024-cell
arenasbob2024-cell

Posted on • Originally published at viadreams.cc

Deno 2 is Here: What Developers Need to Know

#javascript #webdev #node #deno

Deno 2 dropped in October 2024 with full Node.js and npm compatibility. After years of being the "Node killer that nobody uses", Deno 2 is finally ready for production. Here's what changed.

The Big News: npm Compatibility

The original Deno had a fundamental problem: you couldn't use npm packages. Deno 2 fixes this completely.

// Deno 2 - npm packages work directly
import express from "npm:express@4";
import { z } from "npm:zod";

const app = express();
app.get("/", (req, res) => res.json({ hello: "Deno 2" }));
app.listen(3000);
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No node_modules, no package.json required. Just import.

Node.js API Compatibility

Deno 2 implements most Node.js built-ins:

// These Node.js-style imports now work in Deno 2
import fs from "node:fs/promises";
import path from "node:path";
import { createServer } from "node:http";

const data = await fs.readFile("./config.json", "utf-8");
console.log(path.resolve("./output"));
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This means most Node.js packages work without modification.

The Permission System Still Rocks

Deno's security model is still its killer feature:

# Explicit permissions - no more accidental file access
deno run --allow-net --allow-read=./data script.ts

# Deny specific things even if others are allowed
deno run --allow-net --deny-net=evil.com script.ts
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Workspaces and Monorepos

Deno 2 adds workspace support via deno.json:

{
  "workspace": ["./packages/core", "./packages/api", "./packages/ui"]
}
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Each package has its own deno.json with imports and tasks.

Deno Deploy: Serverless at the Edge

Deploy to 35+ regions with zero config:

deno install -g jsr:@deno/deployctl
deployctl deploy --project=my-app --entrypoint=main.ts
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Cold starts under 1ms. No containers, no Lambda cold starts.

Should You Switch?

Use Deno 2 if:

  • Starting a new project (TypeScript-first experience is excellent)
  • Building edge functions (fastest cold starts available)
  • Tired of npm/node_modules complexity

Stick with Node.js if:

  • Large existing codebase with complex dependencies
  • Team not ready to change tooling
  • Need specific npm packages that use native addons

Try It Now

Use the TypeScript Playground on DevToolBox to test TypeScript code before running it with Deno.

The future is serverless and edge-first. Deno 2 is ready for it.

Full Deno 2 guide at viadreams.cc/en/blog/deno-2-guide

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