TypeScript with Node.js

TypeScript with Node.js: Setup, ESM Modules, & Dev Execution

Building Node.js applications with TypeScript requires configuring module resolution, setting up dev execution drivers (tsx or ts-node), and outputting clean compiled code.

Node.js + TypeScript Workflow

flowchart LR
    A["Development: tsx / ts-node"] --> B["Instant Execution (No Dist Output)"]
    C["Production: tsc"] --> D["Emits JavaScript into ./dist"] --> E["node dist/server.js"]

Practical Code Example

Setting up an Express Node.js application in TypeScript (src/server.ts):

import express, { Request, Response } from "express";
import http from "http";

const app = express();
const PORT = process.env.PORT || 3000;

app.use(express.json());

app.get("/api/health", (req: Request, res: Response) => {
  res.json({
    status: "HEALTHY",
    timestamp: new Date().toISOString(),
    uptime: process.uptime()
  });
});

const server = http.createServer(app);

server.listen(PORT, () => {
  console.log(`🚀 Node.js TypeScript server running on http://localhost:${PORT}`);
});

Dev vs Build Scripts in package.json

{
  "scripts": {
    "dev": "tsx watch src/server.ts",
    "build": "tsc",
    "start": "node dist/server.js"
  }
}

Best Practices & Gotchas

• Use tsx for Fast Local Development: tsx uses esbuild under the hood for lightning-fast TypeScript execution without manual compilation steps.
• Include Extension Imports for ESM: When using "module": "NodeNext", Node.js requires explicit .js extensions in import statements (import { util } from "./util.js";).
• Always Install @types/node: Enables global Node.js types (process, Buffer, __dirname).

Self-Check Challenge

What package provides fast zero-config TypeScript execution for Node.js development? (e.g. tsx)