fix(firestore, emulator): avoid double calls to useEmulator

covers case where javascript hot-reloads and loses state then calls again
by tracking state of calls natively

Fixes #5723

Author: mikehardy

packages/firestore/android/src/main/java/io/invertase/firebase/firestore/UniversalFirebaseFirestoreModule.java

@@ -28,11 +28,14 @@
 import io.invertase.firebase.common.UniversalFirebaseModule;
 import io.invertase.firebase.common.UniversalFirebasePreferences;
 import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
 public class UniversalFirebaseFirestoreModule extends UniversalFirebaseModule {
 
+  private static HashMap<String, String> emulatorConfigs = new HashMap<>();
+
   UniversalFirebaseFirestoreModule(Context context, String serviceName) {
     super(context, serviceName);
   }
@@ -49,7 +52,10 @@ Task<Void> useEmulator(String appName, String host, int port) {
     return Tasks.call(
         getExecutor(),
         () -> {
-          getFirestoreForApp(appName).useEmulator(host, port);
+          if (emulatorConfigs.get(appName) == null) {
+            emulatorConfigs.put(appName, "true");
+            getFirestoreForApp(appName).useEmulator(host, port);
+          }
           return null;
         });
   }

packages/firestore/ios/RNFBFirestore/RNFBFirestoreModule.m

@@ -20,6 +20,8 @@
 #import "RNFBFirestoreCommon.h"
 #import "RNFBPreferences.h"
 
+NSMutableDictionary *emulatorConfigs;
+
 @implementation RNFBFirestoreModule
 #pragma mark -
 #pragma mark Module Setup
@@ -142,13 +144,19 @@ + (BOOL)requiresMainQueueSetup {
                   : (FIRApp *)firebaseApp
                   : (nonnull NSString *)host
                   : (NSInteger)port) {
-  FIRFirestore *firestore = [RNFBFirestoreCommon getFirestoreForApp:firebaseApp];
-  [firestore useEmulatorWithHost:host port:port];
-
-  // It is not sufficient to just use emulator. You have toggle SSL off too.
-  FIRFirestoreSettings *settings = firestore.settings;
-  settings.sslEnabled = FALSE;
-  firestore.settings = settings;
+  if (emulatorConfigs == nil) {
+    emulatorConfigs = [[NSMutableDictionary alloc] init];
+  }
+  if (!emulatorConfigs[firebaseApp.name]) {
+    FIRFirestore *firestore = [RNFBFirestoreCommon getFirestoreForApp:firebaseApp];
+    [firestore useEmulatorWithHost:host port:port];
+    emulatorConfigs[firebaseApp.name] = @YES;
+
+    // It is not sufficient to just use emulator. You have toggle SSL off too.
+    FIRFirestoreSettings *settings = firestore.settings;
+    settings.sslEnabled = FALSE;
+    firestore.settings = settings;
+  }
 }
 
 RCT_EXPORT_METHOD(waitForPendingWrites