What is TypeScript?

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It adds optional static typing and class-based object-oriented programming.

Why TypeScript?

• Catch errors early: Find bugs at compile time, not runtime
• Better tooling: Improved autocomplete, refactoring, and navigation
• Self-documenting: Types serve as documentation
• Scalable: Easier to maintain large codebases

Your First TypeScript Program

Type Annotations

In TypeScript, you can add type annotations to variables:

Compilation

TypeScript compiles to JavaScript. Click "Show JS" to see the output:

The types are removed during compilation - they're only for development!

Exercise: Add Types

Add type annotations to the variables: