[Auth] Add missing PhoneMultiFactorInfo public interface (#5924)

* Add missing PhoneMultiFactorInfo public interface

* Fix missing closing paren

* Changeset

Author: sam-gc

.changeset/tame-timers-visit.md

@@ -0,0 +1,5 @@
+---
+"@firebase/auth": patch
+---
+
+Add missing PhoneMultiFactorInfo public interface

common/api-review/auth.api.md

@@ -601,6 +601,11 @@ export class PhoneMultiFactorGenerator {
     static FACTOR_ID: string;
 }
 
+// @public
+export interface PhoneMultiFactorInfo extends MultiFactorInfo {
+    readonly phoneNumber: string;
+}
+
 // @public
 export interface PhoneMultiFactorSignInInfoOptions {
     multiFactorHint?: MultiFactorInfo;

packages/auth/src/mfa/mfa_info.ts

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { FactorId, MultiFactorInfo } from '../model/public_types';
+import { FactorId, MultiFactorInfo, PhoneMultiFactorInfo } from '../model/public_types';
 import {
   PhoneMfaEnrollment,
   MfaEnrollment
@@ -40,13 +40,13 @@ export abstract class MultiFactorInfoImpl implements MultiFactorInfo {
     enrollment: MfaEnrollment
   ): MultiFactorInfoImpl {
     if ('phoneInfo' in enrollment) {
-      return PhoneMultiFactorInfo._fromServerResponse(auth, enrollment);
+      return PhoneMultiFactorInfoImpl._fromServerResponse(auth, enrollment);
     }
     return _fail(auth, AuthErrorCode.INTERNAL_ERROR);
   }
 }
 
-export class PhoneMultiFactorInfo extends MultiFactorInfoImpl {
+export class PhoneMultiFactorInfoImpl extends MultiFactorInfoImpl implements PhoneMultiFactorInfo {
   readonly phoneNumber: string;
 
   private constructor(response: PhoneMfaEnrollment) {
@@ -57,7 +57,7 @@ export class PhoneMultiFactorInfo extends MultiFactorInfoImpl {
   static _fromServerResponse(
     _auth: AuthInternal,
     enrollment: MfaEnrollment
-  ): PhoneMultiFactorInfo {
-    return new PhoneMultiFactorInfo(enrollment);
+  ): PhoneMultiFactorInfoImpl {
+    return new PhoneMultiFactorInfoImpl(enrollment);
   }
 }

packages/auth/src/model/public_types.ts

@@ -628,6 +628,15 @@ export interface MultiFactorInfo {
   readonly factorId: typeof FactorIdMap[keyof typeof FactorIdMap];
 }
 
+/**
+ * The subclass of the {@link MultiFactorInfo} interface for phone number
+ * second factors. The factorId of this second factor is {@link FactorId.PHONE}.
+ */
+export interface PhoneMultiFactorInfo extends MultiFactorInfo {
+  /** The phone number associated with the current second factor. */
+  readonly phoneNumber: string;
+}
+
 /**
  * The class used to facilitate recovery from {@link MultiFactorError} when a user needs to
  * provide a second factor to sign in.