diff --git a/src/auth/auth.ts b/src/auth/auth.ts
index e1fa7d03c..648f7c317 100644
--- a/src/auth/auth.ts
+++ b/src/auth/auth.ts
@@ -38,7 +38,7 @@ export class AngularFireAuth {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
     @Inject(PLATFORM_ID) platformId: Object,
     private zone: NgZone
   ) {
diff --git a/src/core/firebase.app.module.ts b/src/core/firebase.app.module.ts
index 42f34591c..fa370aa72 100644
--- a/src/core/firebase.app.module.ts
+++ b/src/core/firebase.app.module.ts
@@ -34,7 +34,7 @@ export class FirebaseApp implements app.App {
     functions: (region?: string) => FirebaseFunctions;
 }
 
-export function _firebaseAppFactory(options: FirebaseOptions, nameOrConfig?: string | FirebaseAppConfig) {
+export function _firebaseAppFactory(options: FirebaseOptions, nameOrConfig?: string|FirebaseAppConfig|null) {
     const name = typeof nameOrConfig === 'string' && nameOrConfig || '[DEFAULT]';
     const config = typeof nameOrConfig === 'object' && nameOrConfig || {};
     config.name = config.name || name;
diff --git a/src/database-deprecated/database.ts b/src/database-deprecated/database.ts
index dc797fe82..19e80eec4 100644
--- a/src/database-deprecated/database.ts
+++ b/src/database-deprecated/database.ts
@@ -17,8 +17,8 @@ export class AngularFireDatabase {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
-    @Optional() @Inject(RealtimeDatabaseURL) databaseURL:string,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
+    @Optional() @Inject(RealtimeDatabaseURL) databaseURL:string|null,
     zone: NgZone
   ) {
     this.database = zone.runOutsideAngular(() => {
diff --git a/src/database/database.ts b/src/database/database.ts
index cddac9ec5..852e9b414 100644
--- a/src/database/database.ts
+++ b/src/database/database.ts
@@ -13,8 +13,8 @@ export class AngularFireDatabase {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
-    @Optional() @Inject(RealtimeDatabaseURL) databaseURL:string,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
+    @Optional() @Inject(RealtimeDatabaseURL) databaseURL:string|null,
     @Inject(PLATFORM_ID) platformId: Object,
     zone: NgZone
   ) {
diff --git a/src/firestore/firestore.ts b/src/firestore/firestore.ts
index 04f40ee52..dfeb0fe02 100644
--- a/src/firestore/firestore.ts
+++ b/src/firestore/firestore.ts
@@ -108,12 +108,12 @@ export class AngularFirestore {
    */
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
-    @Optional() @Inject(EnablePersistenceToken) shouldEnablePersistence: boolean,
-    @Optional() @Inject(FirestoreSettingsToken) settings: Settings,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
+    @Optional() @Inject(EnablePersistenceToken) shouldEnablePersistence: boolean|null,
+    @Optional() @Inject(FirestoreSettingsToken) settings: Settings|null,
     @Inject(PLATFORM_ID) platformId: Object,
     zone: NgZone,
-    @Optional() @Inject(PersistenceSettingsToken) persistenceSettings: PersistenceSettings|undefined,
+    @Optional() @Inject(PersistenceSettingsToken) persistenceSettings: PersistenceSettings|null,
   ) {
     this.scheduler = new FirebaseZoneScheduler(zone, platformId);
     this.firestore = zone.runOutsideAngular(() => {
@@ -128,7 +128,7 @@ export class AngularFirestore {
       // https://github.com/firebase/firebase-js-sdk/issues/608
       const enablePersistence = () => {
         try {
-          return from(this.firestore.enablePersistence(persistenceSettings).then(() => true, () => false));
+          return from(this.firestore.enablePersistence(persistenceSettings || undefined).then(() => true, () => false));
         } catch(e) {
           return of(false);
         }
diff --git a/src/functions/functions.ts b/src/functions/functions.ts
index f5cc03224..55a18c6a1 100644
--- a/src/functions/functions.ts
+++ b/src/functions/functions.ts
@@ -18,10 +18,10 @@ export class AngularFireFunctions {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
     @Inject(PLATFORM_ID) platformId: Object,
     zone: NgZone,
-    @Optional() @Inject(FunctionsRegionToken) region:string|undefined
+    @Optional() @Inject(FunctionsRegionToken) region:string|null
   ) {
     this.scheduler = new FirebaseZoneScheduler(zone, platformId);
     
diff --git a/src/messaging/messaging.ts b/src/messaging/messaging.ts
index 9d9cb37a0..a2acfad8e 100644
--- a/src/messaging/messaging.ts
+++ b/src/messaging/messaging.ts
@@ -18,7 +18,7 @@ export class AngularFireMessaging {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
     @Inject(PLATFORM_ID) platformId: Object,
     zone: NgZone
   ) {
diff --git a/src/storage/storage.ts b/src/storage/storage.ts
index 4cbadd2f4..958177168 100644
--- a/src/storage/storage.ts
+++ b/src/storage/storage.ts
@@ -22,8 +22,8 @@ export class AngularFireStorage {
 
   constructor(
     @Inject(FirebaseOptionsToken) options:FirebaseOptions,
-    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|undefined,
-    @Optional() @Inject(StorageBucket) storageBucket:string,
+    @Optional() @Inject(FirebaseNameOrConfigToken) nameOrConfig:string|FirebaseAppConfig|null|undefined,
+    @Optional() @Inject(StorageBucket) storageBucket:string|null,
     @Inject(PLATFORM_ID) platformId: Object,
     zone: NgZone
   ) {