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

# concatenate

Function @vite-pwa/workbox-swkit/streams

```ts
concatenate(sourcePromises: Promise<StreamSource>[]): { done: Promise<void>; stream: ReadableStream }
```

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

Returns an object exposing a ReadableStream with 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()).

**Returns:**