tsconfig.json

{
    // Change this to match your project
    "include": ["src/index.js"],

    "compilerOptions": {
      // Tells TypeScript to read JS files, as
      // normally they are ignored as source files
      "allowJs": true,
      // Generate d.ts files
      "declaration": true,
      // This compiler run should
      // only output d.ts files
      "emitDeclarationOnly": true,
      // Don't remove comments
      "removeComments": false,
      // Types should go into this directory.
      // Removing this would place the .d.ts files
      // next to the .js files
      "declarationDir": "types",
      // go to js file when using IDE functions like
      // "Go to Definition" in VSCode
      "declarationMap": true
    }
  }