typescript-conventions

name	typescript-conventions
description	Applies project TypeScript conventions and library-grade module boundaries. Use when writing or editing .ts/.tsx files, designing exported APIs or cross-layer contracts, creating reusable modules, or refactoring dependencies between features, packages, services, and adapters.

Typescript

Open and apply the reference files for the relevant section before working. For exported APIs, reusable modules, or cross-layer changes, read rules/library-boundaries.md before editing. Solid component structure, reactivity, and JSX conventions: solidjs skill (also triggers on Solid .tsx / .ts).

Core Rules

1. Use PascalCase for classes, interfaces, and types; camelCase for variables, functions, and methods; UPPER_SNAKE_CASE for constants.
2. Do not abbreviate variable names, keep them to at most three words, and avoid repeating outer object names in nested variables.
3. Define object shapes with interface; use type only when interface cannot express the type.
4. Avoid any; prefer unknown with type guards, satisfies over as, as const plus unions over enum, and readonly for immutable data.
5. Keep constants at the site of use unless they are genuinely shared or part of a boundary, contract, config, type, test, or file-size concern.
6. Avoid continue (and break when skipping loop body logic). Prefer a single positive if condition, early return, or filter/reduce so the loop body stays one straight path.
7. Never write comments on the right side of code; always write above the target code.
8. Check null/undefined with === null / === undefined.
9. Run oxlint --fix after writing code, then fix remaining lint issues.
10. See ./rules/object-parameter.md when naming a single object parameter on a hook or util.
11. See ./rules/no-types.md when module types are missing.
12. See ./code-patterns/type-guard.md when handling unknown or writing type guards.
13. See ./code-patterns/type-and-value-import.md when importing both a type and a value from the same module.