How to Set Up TypeScript in a Project

Setting Up TypeScript from Scratch

This guide walks you through adding TypeScript to a new or existing Node.js project in under 5 minutes.

Step 1: Install TypeScript

npm init -y
npm install --save-dev typescript @types/node

Step 2: Create tsconfig.json

npx tsc --init

Then set these sensible defaults:

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true
  }
}

Step 3: Write Some TypeScript

// src/index.ts
const greet = (name: string): string => `Hello ${name}`;
console.log(greet("World"));

Step 4: Compile & Run

npx tsc           # compiles src → dist
node dist/index.js

Step 5: Add Handy Scripts

// package.json
"scripts": {
  "build": "tsc",
  "dev": "tsc --watch"
}

Bonus: Run TS Directly with tsx

npm install --save-dev tsx
npx tsx src/index.ts   # no separate compile step

FAQs

What does "strict": true do?

It enables all strict type-checking options (no implicit any, null checks, etc.). Always keep it on for new projects.

Do I commit the dist folder?

No — add dist/ to .gitignore and build during deployment. See more how-to guides.