tsconfig.json

{
	"compilerOptions": {
		"moduleResolution": "node",
		"target": "esnext",
		"module": "esnext",

		/**
		 * svelte-preprocess cannot figure out whether you have
		 * a value or a type, so tell TypeScript to enforce using
		 * `import type` instead of `import` for Types.
		 */
		"isolatedModules": true,
		"resolveJsonModule": true,
		/**
		 * To have warnings / errors of the Svelte compiler at the
		 * correct position, enable source maps by default.
		 */
		"sourceMap": true,
		"esModuleInterop": true,
		"skipLibCheck": true,
		"forceConsistentCasingInFileNames": true,
		"allowSyntheticDefaultImports": true,
		"baseUrl": ".",
		/**
		 * 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,

		/* Custom rules */
		"declaration": true,
		"outDir": "dist",
		"typeRoots": ["./node_modules/@types"]
	},
	/**
	 * Use global.d.ts instead of compilerOptions.types
	 * to avoid limiting type declarations.
	 */
	"include": ["src/**/*", "types/**/*.d.ts"]
}