tsconfig.json

{
  // Tells TypeScript where to look for files to work with.
  "include": ["index.js", "src/**/*"],
  "compilerOptions": {
    // Skip type checking all .d.ts files from external libraries.
    "skipLibCheck": true,
    // Tell TypeScript to read JS files, as normally they are ignored as source files.
    "allowJs": true,
    // Ask Typescript to generate .d.ts declaration files.
    "noEmit": false,
    "declaration": true,
    // This compiler run should only output .d.ts files.
    "emitDeclarationOnly": true,
    // Types should go into this directory.
    // Removing this option will place the .d.ts files next to their .js source files.
    "outDir": "typescript",
    // Generate declaration files to go to js file when using IDE functions like "Go to Definition".
    "declarationMap": true
  }
}