tsconfig.json

{
  "compilerOptions": {
    // Enable top-level await, and other modern ESM features.
    "target": "ESNext",
    "module": "ESNext",
    // Enable node-style module resolution, for things like npm package imports.
    "moduleResolution": "node",
    // Enable JSON imports.
    "resolveJsonModule": true,
    // Enable stricter transpilation for better output.
    "isolatedModules": true,
    // Astro will directly run your TypeScript code, no transpilation needed.
    "noEmit": true,
    // Enable strict type checking.
    "strict": true,
    // Error when a value import is only used as a type.
    "importsNotUsedAsValues": "error",
    // Report errors for fallthrough cases in switch statements
    "noFallthroughCasesInSwitch": true,
    // Force functions designed to override their parent class to be specified as `override`.
    "noImplicitOverride": true,
    // Force functions to specify that they can return `undefined` if a possibe code path does not return a value.
    "noImplicitReturns": true,
    // Report an error when a variable is declared but never used.
    "noUnusedLocals": true,
    // Report an error when a parameter is declared but never used.
    "noUnusedParameters": true,
    // Force the usage of the indexed syntax to access fields declared using an index signature.
    "noUncheckedIndexedAccess": true,
    // Report an error when the value `undefined` is given to an optional property that doesn't specify `undefined` as a valid value.
    "exactOptionalPropertyTypes": true,
    "skipLibCheck": true,
    "jsx": "react-jsx"
  }
}