When building a personal finance tracker, data integrity and system reliability are non-negotiable. One missing try/catch block can crash your whole server, and weak types can let invalid financial payloads corrupt your database.
While building the backend for my personal finance tracker, I decided to move past generic tutorials and build a bulletproof, production-grade API core using Express, TypeScript, and Zod.
In this post, I’ll show you how I implemented a type-safe middleware ecosystem, leveraged TypeScript declaration merging to extend the native Request object, and eliminated repetitive try/catch boilerplate across the entire codebase.
1. The Weapon Against Boilerplate: The asyncHandler HOC
Writing try/catch blocks in every single controller handler clutters code and introduces human error—it’s easy to forget to pass an error to next().
