TypeScript patterns every developer should know
Start Strict, Stay Strict:
Enable strict mode from project day one. It catches null reference bugs, implicit any types, and unsafe casts at compile time, saving hours of runtime debugging in production.
Model Your Domain:
Use discriminated unions and branded types to represent application states explicitly. Instead of optional fields everywhere, model loading, success, and error as distinct types. Your IDE and compiler become your best reviewers.
Share Types Across the Stack:
With tRPC, Zod, or shared monorepo packages, frontend and backend can share the same type definitions. API contracts stay in sync automatically, eliminating an entire class of integration bugs between client and server.
Comments (9)
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Best TypeScript patterns post I've read this year. Sending to the whole frontend team.
Any tips for migrating a large JS codebase to strict TypeScript incrementally?
Enable strict per folder, use allowJs initially, and fix types module by module. Don't big-bang it.
Branded types for user IDs vs order IDs — small pattern, huge safety win.
Shared types with tRPC eliminated half our integration bugs. Great mention.
tRPC + Zod is our default stack now for full-stack TypeScript apps.
Strict mode from day one — wish we'd done this on our legacy codebase sooner.
Discriminated unions changed how we model API responses. Clear and practical advice.
Discriminated unions plus exhaustive switch checks catch so many bugs at compile time.