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Programming Languages

TypeScript.

Static typing for JavaScript — annotations, interfaces, generics, utility types, and advanced type patterns.

Beginner

Start here — no prior experience needed

6 lessons

Intermediate

For developers with core concepts down

12 lessons
typescript intermediate
5 min read

Use the type keyword to create unions, intersections, discriminated unions, and mapped types for expressive and reusable TypeScript code.

typescript intermediate
5 min read

Use access modifiers, abstract classes, parameter properties, and interface implementation to write well-structured object-oriented TypeScript.

typescript intermediate
5 min read

Write reusable, type-safe code with generic functions, classes, constraints, conditional types, and the infer keyword.

typescript intermediate
5 min read

Master TypeScript's built-in utility types: Partial, Required, Readonly, Pick, Omit, Record, ReturnType, Awaited, and more.

typescript intermediate
5 min read

Understand TypeScript modules, namespaces, .d.ts declaration files, and ambient declarations for typing third-party JavaScript.

typescript intermediate
5 min read

Build robust error handling with Result types, exhaustive checks, type guards, and assertion functions in TypeScript.

typescript intermediate
5 min read

Type Promises, async/await, fetch calls, error handling patterns, and concurrent async operations in TypeScript.

typescript intermediate
5 min read

Set up Jest with TypeScript using ts-jest, write typed mocks, and perform type-level testing with expect-type and tsd.

typescript intermediate
5 min read

Implement classic design patterns — Singleton, Factory, Builder, and Strategy — with full type safety in TypeScript.

typescript intermediate
5 min read

Type React components, hooks, events, context, and generic components for production-quality React TypeScript applications.

typescript intermediate
5 min read

Build Express APIs with TypeScript: typed middleware, request/response types, typed environment variables, and project setup.

typescript intermediate
5 min read

Top 30 TypeScript interview questions and answers covering types, generics, advanced patterns, and real-world usage.

Advanced

Production-grade patterns for experienced engineers

3 lessons