voluptasmollitia/docs-exp/firestore_.enableindexeddbpersistence.md

Monorepo for the Firebase JavaScript SDK

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## enableIndexedDbPersistence() function

Attempts to enable persistent storage, if possible.

Must be called before any other functions (other than [initializeFirestore()](./firestore_.initializefirestore.md)<!-- -->, [getFirestore()](./firestore_.getfirestore.md) or [clearIndexedDbPersistence()](./firestore_.clearindexeddbpersistence.md)<!-- -->.

If this fails, `enableIndexedDbPersistence()` will reject the promise it returns. Note that even after this failure, the `Firestore` instance will remain usable, however offline persistence will be disabled.

There are several reasons why this can fail, which can be identified by the `code` on the error.

\* failed-precondition: The app is already open in another browser tab. \* unimplemented: The browser is incompatible with the offline persistence implementation.

<b>Signature:</b>

```typescript
export declare function enableIndexedDbPersistence(firestore: FirebaseFirestore, persistenceSettings?: PersistenceSettings): Promise<void>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  firestore | [FirebaseFirestore](./firestore_.firebasefirestore.md) | The <code>Firestore</code> instance to enable persistence for. |
|  persistenceSettings | [PersistenceSettings](./firestore_.persistencesettings.md) | Optional settings object to configure persistence. |

<b>Returns:</b>

Promise&lt;void&gt;

A promise that represents successfully enabling persistent storage.