tsconfig.json

{
  "compilerOptions": {
    // Project structure
    "rootDir": ".",
    "outDir": "./dist",
    "module": "esnext",
    "target": "esnext",

    "declaration": true, // Generate .d.ts files
    "declarationDir": "./dist/types",
    "emitDeclarationOnly": true,
    "declarationMap": true,

    // Type safety & strictness
    "strict": true, // Enable all strict type checks
    "noUncheckedIndexedAccess": true, // Add undefined to indexed access types
    "exactOptionalPropertyTypes": true, // Optional properties are exactly optional

    // Interop & module resolution
    "esModuleInterop": true, // Allow default imports from CommonJS
    "verbatimModuleSyntax": true, // Use import/export syntax as written
    "moduleResolution": "bundler",
    "moduleDetection": "force", // Only treat files with import/export as modules
    "forceConsistentCasingInFileNames": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,

    "noUncheckedSideEffectImports": true, // Warn on imports with side effects
    "skipLibCheck": true, // Skip type checking of declaration files

    // Types (empty unless you want to include global types)
    "types": ["svelte"],

    // Paths
    "baseUrl": ".",
    "paths": {
      "$lib/*": ["./src/lib/*"],
      "$features/*": ["./src/lib/features/*"],
      "$ui/*": ["./src/lib/components/ui/*"]
    }
  },
  "include": ["src", "svelte.config.js"],
  "exclude": ["node_modules", "dist", "docs"]
}