voluptasmollitia/docs-exp/database.ondisconnect.set.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/database](./database.md) &gt; [OnDisconnect](./database.ondisconnect.md) &gt; [set](./database.ondisconnect.set.md)

## OnDisconnect.set() method

Ensures the data at this location is set to the specified value when the client is disconnected (due to closing the browser, navigating to a new page, or network issues).

`set()` is especially useful for implementing "presence" systems, where a value should be changed or cleared when a user disconnects so that they appear "offline" to other users. See [Enabling Offline Capabilities in JavaScript](https://firebase.google.com/docs/database/web/offline-capabilities) for more information.

Note that `onDisconnect` operations are only triggered once. If you want an operation to occur each time a disconnect occurs, you'll need to re-establish the `onDisconnect` operations each time.

<b>Signature:</b>

```typescript
set(value: unknown): Promise<void>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  value | unknown | The value to be written to this location on disconnect (can be an object, array, string, number, boolean, or null). |

<b>Returns:</b>

Promise&lt;void&gt;

Resolves when synchronization to the Database is complete.