TypeScript Introduction

What is TypeScript?

TypeScript is a programming language developed by Microsoft that builds on JavaScript by adding static type definitions. It is designed to catch errors early in development and enable better tooling for large codebases.

Why Use TypeScript?

• Helps prevent runtime errors with compile-time checks
• Improves code readability and maintainability
• Enables better autocompletion and refactoring in modern IDEs

TypeScript vs JavaScript

TypeScript is a superset of JavaScript, meaning all valid JavaScript code also works in TypeScript. The key difference is that TypeScript adds static typing, interfaces, and advanced type features, which help catch errors during development instead of at runtime. TypeScript must be transpiled into JavaScript using the TypeScript compiler (tsc) before it can run in browsers or Node.js.

• Typing: JavaScript is dynamically typed; TypeScript is statically typed.
• Compilation: JavaScript runs as-is; TypeScript requires compilation to JavaScript.
• Tooling: TypeScript provides better IntelliSense, autocompletion, and refactoring support.
• Error Detection: TypeScript catches type errors during development, while JavaScript errors occur at runtime.
• Extra Features: TypeScript supports interfaces, generics, and enums—features not present in JavaScript.

Setting Up TypeScript

Install TypeScript globally using npm:

npm install -g typescript

To compile a file:

tsc hello.ts

This generates a hello.js file.

Tools and Editors

VS Code is the most popular editor for TypeScript. It provides real-time error highlighting, autocompletion, and intelligent refactoring tools.

Best Practices

• Use type annotations whenever possible
• Write modular code using interfaces and classes
• Use strict mode in tsconfig.json for maximum safety

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