TypeScript for Backend Engineers: Beyond the Basics
Advanced TypeScript patterns for building robust, maintainable backend services — type guards, discriminated unions, generic utilities, and more.
TypeScript’s type system is far more powerful than most engineers use. If you’re still just writing interface Foo { bar: string }, there’s a whole world of type-level programming that can make your backend code safer and more expressive. Let’s explore it.
Discriminated Unions for Type-Safe State
Model states that can’t coexist using discriminated unions:
Type Guards for Runtime Safety
Utility Types You Should Know
Generic Constraints for Reusable Functions
Result Type: Safe Error Handling
Replace try/catch with explicit Result types:
Zod for Runtime Validation
TypeScript types are erased at runtime. Use Zod to validate external data:
Template Literal Types
TypeScript’s type system is Turing-complete. You can encode complex business rules at the type level, making impossible states unrepresentable and catching entire categories of bugs before they reach production.