tsconfig.json

{
  "extends": "@tsconfig/svelte/tsconfig.json",
  "compilerOptions": {
    "strict": true,
    "sourceMap": true,
    "target": "ESNext",
    "module": "ESNext",
    "useDefineForClassFields": true,
    "resolveJsonModule": true,
    "experimentalDecorators": true,
    "forceConsistentCasingInFileNames": true,
    /**
     * Typecheck JS in `.svelte` and `.js` files by default.
     * Disable checkJs if you'd like to use dynamic types in JS.
     * Note that setting allowJs false does not prevent the use
     * of JS in `.svelte` files.
     */
    "allowJs": true,
    "checkJs": true,
    "isolatedModules": true
  },
  // Path aliases are handled by https://kit.svelte.dev/docs/configuration#alias
  //
  // If you want to overwrite includes/excludes, make sure to copy over the relevant includes/excludes
  // from the referenced tsconfig.json - TypeScript does not merge them in
  "include": ["src/**/*.d.ts", "src/**/*.ts", "src/**/*.js", "src/**/*.svelte"],
  "references": [{ "path": "./tsconfig.node.json" }]
}