Troubleshooting Handbook: Globals, Images and other non-TS files

Use declaration merging.

If, say, you are using a third party JS script that attaches on to the window global, you can extend Window:

declare global {
interface Window {
MyVendorThing: MyVendorType;
}
}

Likewise if you wish to "import" an image or other non TS/TSX file:

// declaration.d.ts
// anywhere in your project, NOT the same name as any of your .ts/tsx files
declare module "*.png";
// importing in a tsx file
import * as logo from "./logo.png";

Note that tsc cannot bundle these files for you, you will have to use Webpack or Parcel.

Related issue: https://github.com/Microsoft/TypeScript-React-Starter/issues/12 and StackOverflow