Welcome back! I am Mihir, and in this lesson we will set up TypeScript on your system from scratch.

Before we write serious TypeScript code, we need a basic development environment. Do not worry if setup feels boring. Once this is done, your workflow becomes smooth: write .ts files, check errors, compile to JavaScript, and run the final code.

What We Need to Install

To use TypeScript locally, we need:

Most developers use VS Code because TypeScript support is excellent by default.

Step 1: Install Node.js

TypeScript projects commonly use Node.js tooling, even when the final app runs in the browser.

Go to the official Node.js website and install the LTS version:

https://nodejs.org

After installation, open your terminal and check:

node -v
npm -v

You should see version numbers.

Example:

v22.0.0
10.0.0

If both commands work, Node.js and npm are ready.

Step 2: Create a TypeScript Project Folder

Create a new folder:

mkdir typescript-practice
cd typescript-practice

Initialize a Node project:

npm init -y

This creates a package.json file.

package.json stores project information, scripts, and installed packages.

Step 3: Install TypeScript

Install TypeScript as a development dependency:

npm install typescript --save-dev

Why --save-dev?

Because TypeScript is mainly needed during development. The final output is JavaScript.

After installation, your package.json may include:

{
  "devDependencies": {
    "typescript": "^5.0.0"
  }
}

Step 4: Check TypeScript Version

Run:

npx tsc -v

tsc means TypeScript Compiler.

npx lets you run the local TypeScript compiler installed in your project.

You should see something like:

Version 5.x.x

Step 5: Create Your First TypeScript File

Create a file named:

index.ts

Add this code:

const mentor: string = "Mihir";
const course: string = "TypeScript";

function createMessage(name: string, topic: string): string {
  return `Hello ${name}, welcome to ${topic}!`;
}

console.log(createMessage(mentor, course));

This file uses TypeScript syntax:

• mentor: string
• course: string
• function parameters with types
• function return type

Step 6: Compile TypeScript to JavaScript

Run:

npx tsc index.ts

This creates:

index.js

Open index.js. You will see normal JavaScript:

var mentor = "Mihir";
var course = "TypeScript";
function createMessage(name, topic) {
    return "Hello ".concat(name, ", welcome to ").concat(topic, "!");
}
console.log(createMessage(mentor, course));

The TypeScript types are removed.

That is the key idea:

TypeScript is checked during development.
JavaScript runs in the actual environment.

Step 7: Run the JavaScript File

Run:

node index.js

Output:

Hello Mihir, welcome to TypeScript!

Congratulations. You just compiled and ran TypeScript locally.

Local vs Global TypeScript Installation

You may see tutorials using:

npm install -g typescript

This installs TypeScript globally.

But for real projects, local installation is better:

npm install typescript --save-dev

Local installation keeps each project locked to its own TypeScript version.

Add Useful npm Scripts

Instead of typing npx tsc index.ts every time, you can add scripts in package.json.

{
  "scripts": {
    "build": "tsc index.ts",
    "start": "node index.js"
  }
}

Now run:

npm run build
npm run start

This is cleaner and closer to professional workflow.

Common Setup Errors

Error: node is not recognized

Node.js is not installed correctly or your terminal needs to be restarted.

Try:

node -v

If it still fails, reinstall Node.js and open a new terminal.

Error: tsc is not recognized

Use:

npx tsc -v

If that fails, install TypeScript:

npm install typescript --save-dev

Error: Cannot find package

Run installation again inside your project folder:

npm install

Recommended Folder Structure

For now, keep it simple:

typescript-practice/
├── index.ts
├── index.js
├── package.json
├── package-lock.json
└── node_modules/

Later, we will improve this using:

src/
dist/
tsconfig.json

But beginners should first understand the basic compile-and-run flow.

What You've Learned

You now know how to:

• Install Node.js
• Create a TypeScript project
• Install TypeScript locally
• Use npx tsc
• Create a .ts file
• Compile TypeScript to JavaScript
• Run the compiled JavaScript with Node.js
• Understand local vs global TypeScript installation

What's Next?

In the next lesson, we will write your First TypeScript Program step by step and understand each line deeply.

Need Help?

• Have questions, confusion, or want to know more? Contact me

Setup is a one-time investment. Once your TypeScript environment is ready, learning becomes much more fun.