How to specify filename with client-zip

[chris-rudmin]

I'd like to pass the readable stream to client-zip while providing a filename (different than the fetch response filename).
Is it possible to do this with the current implementation?

[Touffy]

Yes. You need to transform the stream of Responses into a stream of objects with a name property (your custom filename) and an input property (the Response) and optionally lastModified as specified here. You can do that easily with an async generator (because DownloadStreams are AsyncIterable) :

const dlstream = new DownloadStream(yourInputURLsOrRequests)
async function *namedInput() {
  for await (const response of dlstream) yield {
    name: "your custom name.ext",
    input: response,
    lastModified: response.headers.get('Last-Modified')
  }
}
const zipRersponse = downloadZip(namedInput())

Sometime in the near future, it will be possible to use a TransformStream (because all ReadableStreams will be AsyncIterable like a DownloadStream) or the map method inherited on the DownloadStream. And there are quite a few libraries providing map functions on AsyncIterables today, if you prefer.