TypeScript is a game-changer for Node.js development, bringing type safety and modern tooling to your JavaScript codebase. In this guide, I’ll walk you through the exact steps I used to migrate my Node.js project to TypeScript—no prior TypeScript experience required!

1. Install TypeScript and Type Definitions

First, install TypeScript and the Node.js type definitions as development dependencies:

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

2. Initialize TypeScript Configuration

Generate a tsconfig.json file with the following command:

npx tsc --init

This creates a base TypeScript configuration file in your project root.

3. Update tsconfig.json

Open your tsconfig.json and add or update these important fields:

{
  "include": ["**/*.ts"],
  "exclude": ["node_modules"],
  "compilerOptions": {
    "outDir": "./dist"
    // ...other options
  }
}
  • include tells TypeScript to compile all .ts files.
  • exclude prevents node_modules from being compiled.
  • outDir specifies where the compiled JavaScript will go.

4. Rename Your Files to .ts

Rename your existing .js files to .ts. For example:

mv server.js server.ts

Delete the old .js files to avoid confusion.

5. Compile TypeScript Files

Now, compile your TypeScript files:

npx tsc

This will generate JavaScript files in the dist directory (as specified by outDir).

6. Run the Compiled JavaScript

Run your app using Node.js, pointing to the compiled entry file in dist:

node dist/server.js

Or whatever your entry point is.

7. (Optional) Update npm Scripts

For convenience, add a script to your package.json:

"scripts": {
  "build": "npx tsc",
  "start": "node dist/server.js"
}

Now you can run:

npm run build
npm start

Conclusion

That’s it! You’ve successfully added TypeScript support to your Node.js project. Enjoy better type safety, editor autocompletion, and more robust code!

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