voluptasmollitia/docs-exp/auth.initializeauth.md

Monorepo for the Firebase JavaScript SDK

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[Home](./index.md) &gt; [@firebase/auth](./auth.md) &gt; [initializeAuth](./auth.initializeauth.md)

## initializeAuth() function

Initializes an Auth instance with fine-grained control over [Dependencies](./auth.dependencies.md)<!-- -->.

<b>Signature:</b>

```typescript
export declare function initializeAuth(app: FirebaseApp, deps?: Dependencies): Auth;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  app | [FirebaseApp](./app.firebaseapp.md) |  |
|  deps | [Dependencies](./auth.dependencies.md) |  |

<b>Returns:</b>

[Auth](./auth.auth.md)

## Remarks

This function allows more control over the Auth instance than [getAuth()](./auth.getauth.md)<!-- -->. `getAuth` uses platform-specific defaults to supply the [Dependencies](./auth.dependencies.md)<!-- -->. In general, `getAuth` is the easiest way to initialize Auth and works for most use cases. Use `initializeAuth` if you need control over which persistence layer is used, or to minimize bundle size if you're not using either `signInWithPopup` or `signInWithRedirect`<!-- -->.

For example, if your app only uses anonymous accounts and you only want accounts saved for the current session, initialize Auth with:

```js
const auth = initializeAuth(app, {
  persistence: browserSessionPersistence,
  popupRedirectResolver: undefined,
});

```