Why does aws-sdk redefine Blob and ReadableStream types?

[dogukanakkaya]

In packages/types/src/serde.ts defines Blob and ReadableStream types with empty interfaces.

/**
 * @public
 *
 * Declare DOM interfaces in case dom.d.ts is not added to the tsconfig lib, causing
 * interfaces to not be defined. For developers with dom.d.ts added, the interfaces will
 * be merged correctly.
 *
 * This is also required for any clients with streaming interfaces where the corresponding
 * types are also referred. The type is only declared here once since this `@aws-sdk/types`
 * is depended by all `@aws-sdk` packages.
 */
declare global {
  /**
   * @public
   */
  export interface ReadableStream {}
  /**
   * @public
   */
  export interface Blob {}
}

Which causes return types from other modules to infer this, for example Supabase Storage:

download(path: string, options?: {
  transform?: TransformOptions;
}): Promise<{
  data: Blob;
  error: null;
} | {
  data: null;
  error: StorageError;
}>;

So when I try to call functions on Blob like .text(), .arrayBuffer or properties like .type it shows a type error: Property 'text' does not exist on type 'Blob'.

This does not happen in Node, types are exported from @types/node.
But in Deno Blob type is defined in lib.deno.web.d.ts file.

I am not sure what exactly the difference is between having that file in Deno as built-in to it or having it installed as a node package maybe the order of Typescript interprets it but not sure. Anyways I wonder why does aws-sdk defines those as empty interfaces in the first place?