TypeScript Get Started

To use TypeScript on your computer you need Node.js and the TypeScript compiler, called tsc.

Step 1: Install Node.js

Download Node.js (the LTS version) from its official website and install it. It comes with npm, the Node package manager. Check that both work in a terminal (Command Prompt, PowerShell or Terminal):

node -v
npm -v

v22.11.0
10.9.0

Your version numbers may be different. Any recent version is fine.

Step 2: Install TypeScript

Install TypeScript inside your project folder:

mkdir ts-practice
cd ts-practice
npm init -y
npm install --save-dev typescript
npx tsc -v

Version 5.6.3

npx runs the tsc that is installed in your project.

Step 3: Write a TypeScript File

Create a file called hello.ts:

const student: string = "Ali";
const marks: number = 88;

function report(name: string, score: number): string {
  return `${name} scored ${score} out of 100`;
}

console.log(report(student, marks));

Step 4: Compile and Run

npx tsc hello.ts
node hello.js

Ali scored 88 out of 100

tsc checks the types and creates hello.js, a plain JavaScript file. Node.js then runs that file. If there is a type error, tsc prints it with the file name and line number.

What the Compiled File Looks Like

Open hello.js. The types are gone:

const student = "Ali";
const marks = 88;
function report(name, score) {
    return `${name} scored ${score} out of 100`;
}
console.log(report(student, marks));

Step 5: Create tsconfig.json

Real projects have a tsconfig.json file with the compiler settings. Create one with:

npx tsc --init

A simple setup looks like this:

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "NodeNext",
    "strict": true,
    "outDir": "dist",
    "rootDir": "src"
  }
}

Now put your .ts files in src, and just run npx tsc to compile the whole project. Add --watch to recompile every time you save.

Exercise