voluptasmollitia/docs-exp/database.usedatabaseemulator.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/database](./database.md) &gt; [useDatabaseEmulator](./database.usedatabaseemulator.md)

## useDatabaseEmulator() function

Modify the provided instance to communicate with the Realtime Database emulator.

<p>Note: This method must be called before performing any other operation.

<b>Signature:</b>

```typescript
export declare function useDatabaseEmulator(db: FirebaseDatabase, host: string, port: number): void;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  db | [FirebaseDatabase](./database.firebasedatabase.md) | The instance to modify. |
|  host | string | The emulator host (ex: localhost) |
|  port | number | The emulator port (ex: 8080) |

<b>Returns:</b>

void