tsconfig.base.json

{
  "compilerOptions": {
    // Module resolution
    "module": "commonjs",
    "moduleResolution": "node",
    "target": "ES2021",
    "lib": ["ES2021"],
    
    // Output
    "declaration": true,
    "sourceMap": true,
    "removeComments": true,
    "outDir": "./dist",
    "baseUrl": "./",
    
    // Decorators (required for NestJS)
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    
    // Performance
    "incremental": true,
    "skipLibCheck": true,
    
    // Interop
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    
    // Safety
    "noFallthroughCasesInSwitch": true,
    
    // Strict mode - enables all strict type checking options
    "strict": true
    
    /* 
     * The "strict" flag above is equivalent to enabling:
     * - strictNullChecks: true
     * - noImplicitAny: true  
     * - strictBindCallApply: true
     * - strictFunctionTypes: true
     * - strictPropertyInitialization: true
     * - noImplicitThis: true
     * - alwaysStrict: true
     * - useUnknownInCatchVariables: true (TS 4.4+)
     */
  }
}