TypeScript Mastery: Top 6 Features You Should Be Using in 2025

TypeScript has become the go-to language for large-scale JavaScript applications. While basic types and interfaces are widely used, there’s a lot more under the hood. If you want to truly master TypeScript, here are 6 powerful features you should start using today.

1. Template Literal Types

Leverage template strings in your types for advanced pattern matching. Great for building frameworks or API clients with predictable naming schemes.

tsCopyEdittype HttpMethod = 'GET' | 'POST' | `PUT_${string}`;

2. Satisfies Operator

Ensure an object matches a shape without losing inferred type information.

tsCopyEditconst config = {
  theme: 'dark',
  version: 1.2
} satisfies AppConfig;

3. Discriminated Unions

Simplify complex state handling and API responses using unions with literal properties.

tsCopyEdittype Response = { status: 'success'; data: User } | { status: 'error'; error: string };

4. Infer and Conditional Types

Build flexible and reusable utility types by using infer to extract types.

tsCopyEdittype ReturnType<T> = T extends (...args: any[]) => infer R ? R : never;

5. Mapped & Remapped Types

Powerfully transform and rename object types dynamically using mapped types.

tsCopyEdittype PrefixKeys<T> = {
  [K in keyof T as `app_${string & K}`]: T[K];
};

6. Decorators (Experimental)

Decorators are now closer to standard. Use them for meta-programming and class transformations in frameworks like Angular and NestJS.

Final Thoughts

Mastering TypeScript means going beyond types and interfaces—it’s about using the type system as a tool for abstraction, safety, and automation. These features can level up your code quality and help you build rock-solid applications in 2025.