What You Should Know Now — and What's Next

What You Should Know Now

• The type system: annotations, inference, unions, literal types, enums
• Interfaces, type aliases, and when to reach for each
• Generics, from basic reusable functions to constrained/advanced generics
• Classes with access modifiers, and implementing interfaces
• Working safely with untyped third-party JavaScript
• Advanced type-level features: conditional types, mapped types, template literal types
• How to configure tsconfig.json, including strict mode
• How to migrate an existing JavaScript codebase incrementally

What Should You Learn Next?

• A frontend framework with TypeScript — React, Vue, or Angular all have first-class TypeScript support, building directly on the types you just learned.
• NestJS — a Node.js backend framework built TypeScript-first, making heavy use of decorators and dependency injection.
• Zod or a similar schema library — for validating external data (API responses, form input) against a type at runtime, closing the gap this course flagged around as assertions.

Build Something

Pick a project idea that solves an actual problem you personally have — and build it in TypeScript from the start this time, rather than retrofitting types onto working JavaScript. Writing the types first often clarifies the design before you write any implementation at all.