---
url: /api/symbols/workbox-swkit/streams/concatenatetoresponse.md
---

# concatenateToResponse

Function @vite-pwa/workbox-swkit/streams

```ts
concatenateToResponse(sourcePromises: Promise<StreamSource>[], headersInit?: HeadersInit): { done: Promise<void>; response: Response }
```

Takes multiple source Promises, each of which could resolve to a Response, a
ReadableStream, or a [BodyInit](https://fetch.spec.whatwg.org/#bodyinit),
along with a
[HeadersInit](https://fetch.spec.whatwg.org/#typedefdef-headersinit).

Returns an object exposing a Response whose body consists of each individual
stream's data returned in sequence, along with a Promise which signals when
the stream is finished (useful for passing to a FetchEvent's waitUntil()).

### Parameters

* `headersInit` – If there's no `Content-Type` specified,
  `'text/html'` will be used by default.

**Returns:**