TypeScript Tutorial

1. TypeScript Introduction

Why add types to JavaScript, installing TypeScript, tsconfig.json basics, and compiling with tsc.

2. TypeScript Types Basics

Primitives, interfaces vs type aliases, union/intersection types, arrays, tuples, and optional/readonly properties.

3. Modules and Namespaces

Module resolution strategies, import type, and legacy namespaces for reading older TypeScript code.

4. Advanced TypeScript Types

Generics, utility types like Partial and Pick, and type narrowing with typeof, in and discriminated unions.

5. Advanced Generics and Conditional Types

Generic constraints with keyof, conditional types, the infer keyword, and mapped types with a real validation example.

6. Classes and Decorators

Access modifiers, interfaces implemented by classes, abstract classes, and writing a class decorator.

7. Testing TypeScript

Typing mocks and test helpers, narrowing unknown caught errors, and a complete typed Vitest/Jest test file.

8. TypeScript Interview Questions

Real TypeScript interview questions and answers covering interfaces, generics, unknown vs any, and structural typing.