---
url: /api/symbols/workbox-window/messagesw.md
---

# messageSW

Function @vite-pwa/workbox-window

```ts
messageSW(sw: ServiceWorker, data: any): Promise<unknown>
```

Sends a data object to a service worker via `postMessage` and resolves with
a response (if any).

A response can be set in a message handler in the service worker by
calling `event.ports[0].postMessage(...)`, which will resolve the promise
returned by `messageSW()`. If no response is set, the promise will not
resolve.

### Parameters

* `sw` – The service worker to send the message to.

* `data` – An object to send to the service worker.

**Returns:**