[Home](./index.md) > [@firebase/auth](./auth.md) > [linkWithPopup](./auth.linkwithpopup.md)
## linkWithPopup() function
Links the authenticated provider to the user account using a pop-up based OAuth flow.
Signature:
```typescript
export declare function linkWithPopup(user: User, provider: AuthProvider, resolver?: PopupRedirectResolver): Promise;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| user | [User](./auth.user.md) | The user. |
| provider | [AuthProvider](./auth.authprovider.md) | The provider to authenticate. The provider has to be an [OAuthProvider](./auth.oauthprovider.md). Non-OAuth providers like [EmailAuthProvider](./auth.emailauthprovider.md) will throw an error. |
| resolver | [PopupRedirectResolver](./auth.popupredirectresolver.md) | An instance of [PopupRedirectResolver](./auth.popupredirectresolver.md), optional if already supplied to [initializeAuth()](./auth.initializeauth.md) or provided by [getAuth()](./auth.getauth.md). |
Returns:
Promise<[UserCredential](./auth.usercredential.md)>
## Remarks
If the linking is successful, the returned result will contain the user and the provider's credential.
## Example
```javascript
// Sign in using some other provider.
const result = await signInWithEmailAndPassword(auth, email, password);
// Link using a popup.
const provider = new FacebookAuthProvider();
await linkWithPopup(result.user, provider);
```