How to Set Up a Node.js Project with TypeScript and Express

Setting up a Node.js project with TypeScript and Express gives your app structure, scalability, and clarity. In this guide, we’ll walk step-by-step through initializing your Node.js project, integrating TypeScript, Express, and adding essential developer tools.

Step 1: Initialize Your Node.js Project

Create your project folder and initialize npm:

mkdir my-node-project
cd my-node-project
npm init -y

This generates a package.json. Next, create a .gitignore to exclude node modules and build files:

node_modules
dist

Step 2: Add TypeScript

Install TypeScript and related dependencies:

npm install --save-dev typescript ts-node @types/node

Create your TypeScript configuration with:

npx tsc --init

Adjust your tsconfig.json to look like:

{
  "compilerOptions": {
    "target": "ES2016",
    "module": "commonjs",
    "rootDir": "./src",
    "outDir": "./dist",
    "esModuleInterop": true,
    "strict": true,
    "skipLibCheck": true
  }
}

Create the src folder for your code:

mkdir src

Step 3: Set Up Express

Install Express and its types:

npm install express
npm install --save-dev @types/express

Create a basic server at src/index.ts:

import express, { Application, Request, Response } from 'express';

const app: Application = express();
const PORT = 3000;

app.get('/', (req: Request, res: Response) => {
  res.send('Hello, TypeScript + Express!');
});

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

Run it using:

npx ts-node src/index.ts

Step 4: ESLint and Prettier Setup

Install ESLint, Prettier, and plugins:

npm install --save-dev eslint prettier @typescript-eslint/parser @typescript-eslint/eslint-plugin eslint-plugin-prettier eslint-config-prettier

Set up ESLint with .eslintrc.json:

{
  "parser": "@typescript-eslint/parser",
  "plugins": ["@typescript-eslint", "prettier"],
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:prettier/recommended"
  ],
  "env": { "node": true, "es6": true, "jest": true }
}

Create .prettierrc.json:

{
  "semi": true,
  "singleQuote": true,
  "trailingComma": "all"
}

Update your scripts in package.json:

"scripts": {
  "lint": "eslint 'src/**/*.{ts,js}'",
  "format": "prettier --write ."
}

Step 5: Jest for Testing

Add Jest and TypeScript support:

npm install --save-dev jest ts-jest @types/jest
npx ts-jest config:init

Write a simple test src/__tests__/sum.test.ts:

import { sum } from '../sum';

test('sum works', () => {
  expect(sum(1, 2)).toBe(3);
});

With corresponding module:

export function sum(a: number, b: number): number {
  return a + b;
}

Update package.json:

"scripts": {
  "test": "jest --watch"
}

Step 6: Nodemon for Development

Install and configure nodemon:

npm install --save-dev nodemon

Add nodemon.json:

{
  "watch": ["src"],
  "ext": "ts,json",
  "ignore": ["src/**/*.test.ts"],
  "exec": "ts-node ./src/index.ts"
}

Script for dev environment in package.json:

"scripts": {
  "dev": "nodemon"
}

Run npm run dev to auto-reload your server during development.

Best Practices

• Use separate folders (src for code, dist for build outputs).
• Commit only source files, not compiled code (dist) or node modules.
• Run npm run lint and npm run format frequently.
• Compile code (npm run build) before deployment, then start with npm start.

FAQs