010112-typescript-ruleslisted

# TypeScript Rules ## Overview TypeScript 5.7+ language patterns covering strict mode configuration, type safety, advanced typesystem constructs, best practices, Zod validation, and incremental migration from JavaScript. ## Quick Reference ### Strict Mode ```json { "compilerOptions": { "strict": true, "noUncheckedIndexedAccess": true, "exactOptionalPropertyTypes": true } } ``` ### Core Rules - No `any` — use `unknown`, generics, or `Record<string, unknown>` - No `enum` — union literals (`type Status = "active" | "inactive"`) or `as const` - No `!` non-null assertions — use guards or `Result<T, E>` - No `@ts-ignore` — `@ts-expect-error` only for intentional error tests - `import type` / `export type` for type-only imports - Strict equality `===`, `const` by default ### Type System - Discriminated unions for exhaustive checking - Generics with constraints (`<T extends { id: string }>`) - Mapped types (`Partial<T>`, `Immutable<T>`, `Getters<T>`) - Conditional types (`IsString<T>`, `ArrayElement<T>`, `Awaited<T>`) - `satisfies` operator for compile-time validation - Zod schemas for runtime validation at boundaries ## References - [Type Safety](references/type-safety.md) — Strict mode, no any, discriminated unions, type guards - [Advanced Types](references/advanced-types.md) — Generics, mapped types, conditional types, satisfies - [Rules & Anti-Patterns](references/rules-anti-patterns.md) — No enum, import type, Zod, Result pattern, all lint rules (merged)