voluptasmollitia/docs-exp/messaging.messagepayload.collapsekey.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/messaging](./messaging.md) &gt; [MessagePayload](./messaging.messagepayload.md) &gt; [collapseKey](./messaging.messagepayload.collapsekey.md)

## MessagePayload.collapseKey property

The collapse key of the message. See [Non-collapsible and collapsible messages](https://firebase.google.com/docs/cloud-messaging/concept-options#collapsible_and_non-collapsible_messages)

<b>Signature:</b>

```typescript
collapseKey: string;
```