veritatisdoloremque/docs-exp/database.reference.transaction.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/database](./database.md) &gt; [Reference](./database.reference.md) &gt; [transaction](./database.reference.transaction.md)

## Reference.transaction() method

<b>Signature:</b>

```typescript
transaction(
    transactionUpdate: (a: any) => any,
    onComplete?: (a: Error | null, b: boolean, c: DataSnapshot | null) => any,
    applyLocally?: boolean
  ): Promise<any>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  transactionUpdate | (a: any) =&gt; any |  |
|  onComplete | (a: Error \| null, b: boolean, c: [DataSnapshot](./database.datasnapshot.md) \| null) =&gt; any |  |
|  applyLocally | boolean |  |

<b>Returns:</b>

Promise&lt;any&gt;