tsconfig.json

{
  // tsconfig.json tells TypeScript HOW to check your code.
  // Vite/esbuild does the actual compiling — tsc here is only a type-checker.
  "compilerOptions": {
    /* Language target */
    "target": "ES2022",
    "lib": ["ES2022", "DOM", "DOM.Iterable"], // DOM = browser APIs (fetch, document...)
    "useDefineForClassFields": true,

    /* Modules — let Vite handle bundling */
    "module": "ESNext",
    "moduleResolution": "bundler",
    "allowJs": true, // let .jsx and .tsx coexist during the migration
    "isolatedModules": true, // required because esbuild compiles one file at a time
    "verbatimModuleSyntax": true, // forces `import type {...}` for type-only imports
    "moduleDetection": "force",
    "noEmit": true, // tsc never writes files — it only reports type errors

    /* React */
    "jsx": "react-jsx", // new JSX transform: no need to `import React`

    /* The whole reason we're doing this */
    "strict": true, // turns on every strict type check at once
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noFallthroughCasesInSwitch": true,
    "noUncheckedSideEffectImports": true,

    "skipLibCheck": true // don't type-check node_modules — just trust them
  },
  "include": ["src"]
}