domain:typescript

What problem does it solve?

Consolidates TypeScript project conventions to ensure consistent type safety, robust testing, and standardized error handling across codebases.

Core Features & Use Cases

• Enforce strict mode in tsconfig.json — no exceptions
• Prefer const over let; never use var
• Use discriminated unions for state modeling over class hierarchies
• Prefer unknown over any — narrow types explicitly
• Use readonly on properties and arrays that should not be mutated
• Prefer interface for object shapes, type for unions and intersections
• Use template literal types for string patterns where useful
• Prefer satisfies operator to validate types without widening
• Project structure: src directory, path aliases, barrel exports, colocate tests and types
• Testing: vitest as the test framework; colocate tests with sources
• Error Handling: typed error classes with a code; Result pattern; validate external input with zod
• Dependencies: zod for runtime validation, date-fns for dates, native fetch or ofetch, eslint + prettier, tsup for libraries, vite for applications
• Anti-patterns: avoid any, avoid deep barrel exports, avoid mutable shared state

Quick Start

Apply the conventions by enabling strict mode in tsconfig.json, preferring const over let, using unknown over any, and adopting vitest tests with zod validations.