tsconfig.json

{
    "extends": "@tsconfig/svelte/tsconfig.json",
    "include": ["src"],
    "exclude": ["node_modules", "dist"],
    "compilerOptions": {
        "allowJs": false,
        "target": "ES2020",
        "module": "esnext",
        "lib": ["dom", "esnext"],
        "importHelpers": true,
        // output .d.ts declaration files for consumers
        "declaration": true,
        // output .js.map sourcemap files for consumers
        "sourceMap": true,
        // stricter type-checking for stronger correctness. Recommended by TS
        "strict": true,
        // linter checks for common issues
        "noImplicitReturns": true,
        "noFallthroughCasesInSwitch": true,
        // noUnused* overlap with @typescript-eslint/no-unused-vars, can disable if duplicative
        "noUnusedLocals": true,
        "noUnusedParameters": true,
        // use Node's module resolution algorithm, instead of the legacy TS one
        "moduleResolution": "node",
        // interop between ESM and CJS modules. Recommended by TS
        "esModuleInterop": true,
        // significant perf increase by skipping checking .d.ts files, particularly those in node_modules. Recommended by TS
        "skipLibCheck": true,
        // error out if import and file system have a casing mismatch. Recommended by TS
        "forceConsistentCasingInFileNames": true,
        // `tsdx build` ignores this option, but it is commonly used when type-checking separately with `tsc`
        "noEmit": true
    }
}