typescript-conventionslisted

# TypeScript Conventions This file is self-contained for day-to-day use. Deeper reference (needs the full harness checkout): `languages/typescript/CONVENTIONS.md` (full examples including generics and import grouping) and `frameworks/react/CONVENTIONS.md` (React/JSX-specific additions). ## Naming - `camelCase` — functions, variables, method names. `PascalCase` — classes, interfaces, type aliases, enum names. `UPPER_SNAKE_CASE` — module-level constants. - Enum members: `PascalCase`. - Generic type params: `T`/`U` for simple one-liners; descriptive names (`TEntity`, `TResponse`) for complex or nested generics. ## Imports & module structure Group: external packages → internal modules → type-only imports. Separate each group with a blank line. Prefer `import type` for type-only imports (helps tools that strip types without full parsing). ```typescript import fs from 'fs'; import express from 'express'; import { UserRepository } from './repositories/UserRepository'; import type { User } from './types'; ``` ## Private members: `#` over `_prefix` Prefer native `#` private fields (ES2022+/TS 3.8+) in new code — real runtime privacy, not a convention that's still readable via `["_name"]`. Don't rewrite working `_prefix` code on sight; it's not deprecated. ```typescript class TokenStore { #tokens: Map<string, string> = new Map(); // true runtime privacy #rotate(): void { /* ... */ } } ``` ## Null vs. Undefined Pick based on what *absence means*, then apply it c