tsconfig.json

{
  "$schema": "https://json.schemastore.org/tsconfig",
  "compilerOptions": {
    "allowJs": false,
    "module": "Preserve",

    // ASTRO BASE TSCONFIG (https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/base.json)
    // Enable top-level await, and other modern ESM features.
    "target": "ESNext",
    // "module": "ESNext",
    // Enable module resolution without file extensions on relative paths, for things like npm package imports.
    // "moduleResolution": "Bundler",
    // Allow importing TypeScript files using their native extension (.ts(x)).
    "allowImportingTsExtensions": true,
    // Enable JSON imports.
    // "resolveJsonModule": true,
    // Enforce the usage of type-only imports when needed, which helps avoiding bundling issues.
    "verbatimModuleSyntax": true,
    // Ensure that each file can be transpiled without relying on other imports.
    // This is redundant with the previous option, however it ensures that it's on even if someone disable `verbatimModuleSyntax`
    "isolatedModules": true,
    // Astro directly run TypeScript code, no transpilation needed.
    "noEmit": true,
    // Report an error when importing a file using a casing different from another import of the same file.
    "forceConsistentCasingInFileNames": true,
    // Properly support importing CJS modules in ESM
    // "esModuleInterop": true,
    // Skip typechecking libraries and .d.ts files
    "skipLibCheck": true,
    // Allow JavaScript files to be imported
    // "allowJs": true,
    // Allow JSX files (or files that are internally considered JSX, like Astro files) to be imported inside `.js` and `.ts` files.
    // "jsx": "preserve",

    // ASTRO STRICT TSCONFIG (https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/strict.json)
    // Enable strict mode. This enables a few options at a time, see https://www.typescriptlang.org/tsconfig#strict for a list.
    "strict": true,

    // ASTRO STRICTEST TSCONFIG (https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/strictest.json)
    // 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 possible 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,
    // Report an error for unreachable code instead of just a warning.
    "allowUnreachableCode": false,
    // Report an error for unused labels instead of just a warning.
    "allowUnusedLabels": false
  },
  "include": ["./**/*"]
}