Fix IdpTask types

Author: sam-gc

packages-exp/auth-exp/src/core/strategies/idp.ts

@@ -17,19 +17,16 @@
 
 import * as externs from '@firebase/auth-types-exp';
 
-import {
-  signInWithIdp,
-  SignInWithIdpRequest
-} from '../../api/authentication/idp';
+import { signInWithIdp, SignInWithIdpRequest } from '../../api/authentication/idp';
+import { PhoneOrOauthTokenResponse } from '../../api/authentication/mfa';
 import { Auth } from '../../model/auth';
+import { IdTokenResponse } from '../../model/id_token';
 import { User, UserCredential } from '../../model/user';
+import { AuthCredential } from '../credentials';
 import { _link as _linkUser } from '../user/link_unlink';
 import { _reauthenticate } from '../user/reauthenticate';
 import { assert, debugFail } from '../util/assert';
 import { signInWithCredential } from './credential';
-import { AuthCredential } from '../credentials';
-import { IdTokenResponse } from '../../model/id_token';
-import { PhoneOrOauthTokenResponse } from '../../api/authentication/mfa';
 
 export interface IdpTaskParams {
   auth: Auth;
@@ -92,21 +89,21 @@ class IdpCredential implements AuthCredential {
 
 export function _signIn(
   params: IdpTaskParams
-): Promise<externs.UserCredential> {
-  return signInWithCredential(params.auth, new IdpCredential(params));
+): Promise<UserCredential> {
+  return signInWithCredential(params.auth, new IdpCredential(params)) as Promise<UserCredential>;
 }
 
 export function _reauth(
   params: IdpTaskParams
-): Promise<externs.UserCredential> {
+): Promise<UserCredential> {
   const { auth, user } = params;
   assert(user, auth.name);
   return _reauthenticate(user, new IdpCredential(params));
 }
 
 export async function _link(
   params: IdpTaskParams
-): Promise<externs.UserCredential> {
+): Promise<UserCredential> {
   const { auth, user } = params;
   assert(user, auth.name);
   return _linkUser(user, new IdpCredential(params));