TypeScript / JavaScript

Critical rules for TypeScript and JavaScript development.

Types & Safety

• •Use strict TypeScript (strict: true); avoid any, unknown only when truly unknown
• •Prefer interface for object shapes; type for unions/intersections/utilities
• •No implicit any; explicit return types on exported functions
• •Use as const for literals; avoid type assertions (as) unless unavoidable
• •Nullish: prefer ?? over ||; use optional chaining ?. over manual checks

Code Style

• •const by default; let only when mutation needed; never var
• •Destructure props/objects at function entry
• •Arrow functions for callbacks; named functions for top-level/exported

Async & Error Handling

• •Always await promises or explicitly handle them; no floating promises
• •Use try/catch for async; propagate errors with context
• •Avoid .then()/.catch() chains; prefer async/await

Modules & Imports

• •Imports at file top, grouped: external → internal → types
• •Prefer named exports; default exports only for pages/components where framework requires
• •No circular imports