Setting Up TypeScript

Before coding, we need setup.

Step 1: Install Node.js

TypeScript runs on Node.js.
Download from nodejs.org.

Step 2: Install TypeScript compiler

npm install -g typescript

Check:

tsc -v

Step 3: First TypeScript file

Create file: app.ts

let message: string = "Hello TypeScript";
console.log(message);

Step 4: Compile to JavaScript

tsc app.ts

This creates app.js.

Run:

node app.js

tsconfig.json (project setup)

tsc --init

This creates tsconfig.json which controls:

• target JS version
• strict mode
• module system

Graph: build cycle

flowchart LR
  A[Write app.ts] --> B[tsc]
  B --> C[app.js]
  C --> D[node]

Remember

• write .ts
• compile to .js
• run JavaScript