Code Style

Code Style

TypeScript

• strict: true everywhere — tsc --noEmit must report 0 errors.
• No any without justification — prefer unknown + type guards.
• No @ts-ignore — use @ts-expect-error with a reason.
• Use consistent-type-imports.
• Write compact code: collapse duplicate branches, avoid needless nesting, share abstractions instead of copy-pasting.
• Match the existing style of the file/module you are editing — look at neighboring code before introducing new patterns.

Property header (mandatory)

Every source file must begin with the property header:

// ==============================================================================
// Property of Ralf Carsjens - All Rights Reserved.
// Proprietary and Confidential.
// Unauthorized copying of this file, via any medium, is strictly prohibited.
// Standard: ISO 27001 Compliance | Security-First | Modular API Architecture
// ==============================================================================

Exceptions: standard JSON files (package.json, tsconfig.json), generated files (dist/, .next/, node_modules/), lockfiles.

Language

• Code, identifiers, and code comments: English.
• User-facing UI strings: via next-intl messages (German default).
• Explanations and documentation for the owner: German; developer-facing technical documentation (this site): English.

Error handling

• Handle errors at meaningful boundaries — not every line needs a try/catch. Follow the error-handling style of the surrounding code.
• Throw specific error classes; the global exception filter maps them to TT-xxx codes — see Error Codes.

Input validation & security basics

• Every API endpoint validates input (DTOs + class-validator).
• No string interpolation in SQL — parameterized queries / Prisma only.
• File operations on user input require path sanitization.
• No eval() or dynamic code execution. No dangerouslySetInnerHTML except sanitized/static content.
• No PII in logs — no emails, names, addresses in logger.* output or test output.

Testing conventions

• A setup() function per spec file encapsulates wiring (no shared beforeEach state).
• Assert specific error classes: rejects.toThrow(SpecificError).
• Verify tenant isolation in every service test.
• No any in tests except where strictly needed for mocks.
• No PII in fixtures — synthetic UUIDs, example.com addresses.