nodejs-typescript-foundation

# Node.js TypeScript Foundation ## When to use - Bootstrapping a new Node.js TypeScript project - Auditing an existing project's foundational tooling - Adding strict type-checking and linting ## Core rules 1. `tsconfig.json` must enable `strict: true`, `noImplicitAny: true`, `strictNullChecks: true` 2. ESLint with `@typescript-eslint` parser, no `any`, no `console.log` in production 3. Prettier for formatting, integrated with ESLint 4. Package layout: `src/`, `dist/`, `tests/`, npm scripts for build/lint/test 5. All third-party libs must have `@types/*` packages installed ## Reference shape (TypeScript) ### tsconfig.json ```json { "compilerOptions": { "target": "ES2022", "module": "commonjs", "lib": ["ES2022"], "outDir": "./dist", "rootDir": "./src", "strict": true, "noImplicitAny": true, "strictNullChecks": true, "esModuleInterop": true, "skipLibCheck": true, "forceConsistentCasingInFileNames": true, "resolveJsonModule": true, "moduleResolution": "node", "declaration": true, "declarationMap": true, "sourceMap": true }, "include": ["src/**/*"], "exclude": ["node_modules", "dist", "tests"] } ``` ### ESLint config (.eslintrc.json) ```json { "parser": "@typescript-eslint/parser", "plugins": ["@typescript-eslint"], "extends": [ "eslint:recommended", "plugin:@typescript-eslint/recommended", "prettier" ], "rules": { "@typescript-eslint/no-explicit-any": "error", "@typescript-eslint/no-unused-vars": "error", "no-console": ["warn", { "allow": ["warn", "error"] }] } } ``` ## Examples — Do ```typescript // Strict typing, explicit returns class UserService { constructor(private readonly repository: UserRepository) {} async findById(id: string): Promise<User | null> { return this.repository.findById(id); } } ``` ## Examples — Don't ```typescript // ❌ any, no typing function getUser(id) { return db.query(`SELECT * FROM users WHERE id = ${id}`); } ``` ## Checklist - [ ] `tsconfig.json` with strict flags - [ ] ESLint + Prettier configured - [ ] npm scripts: `build`, `lint`, `test`, `dev` - [ ] `.gitignore` with `node_modules/`, `dist/` - [ ] `src/` and `tests/` folders created See [reference/foundation-setup.md](./reference/foundation-setup.md) for full setup guide.