General JavaScript/TypeScript

To centralize environment configuration in JS/TS services, move all runtime configuration and validated environment access into a dedicated src/config directory. This prevents scattered process.env usage and enables fail-fast startup behavior across modules.

The best way to structure typed error handling in TypeScript is to place typed Error classes in a dedicated src/errors directory. This isolates error management and ensures consistent, typed error boundaries across application modules.

To organize framework-agnostic utilities in a JS/TS codebase, isolate reusable helpers into a dedicated src/utils directory. This separates pure logic from application code and maintains consistent module boundaries for easier refactoring.

Defining explicit input and output types for API boundaries in TypeScript prevents leaky imports and ensures response shapes remain stable. This practice stops modules from returning raw database objects, creating maintainable architecture.

Yes, you can use this code hygiene refactoring approach for stabilizing existing JavaScript services. It applies to refactoring tasks where configuration, utilities, typed error handling, and API boundaries must be reorganized consistently across modules.