fix(remote-config, other): return friendly error for onConfigUpdated

Author: mikehardy

packages/remote-config/e2e/config.e2e.js

@@ -781,9 +781,20 @@ describe('remoteConfig()', function () {
       });
     });
 
-    xdescribe('onConfigUpdated', function () {
+    describe('onConfigUpdated on un-supported platforms', function () {
+      it('returns a descriptive error message if called', async function () {
+        const { getRemoteConfig, onConfigUpdated } = remoteConfigModular;
+        try {
+          onConfigUpdated(getRemoteConfig());
+        } catch (error) {
+          error.message.should.containEql('Not supported by the Firebase Javascript SDK');
+        }
+      });
+    });
+
+    xdescribe('onConfigUpdated on supported platforms', function () {
       if (Platform.other) {
-        // Not supported on Web.
+        // Not supported on Web, verify we get a nice error
         return;
       }
 

packages/remote-config/lib/web/RNFBConfigModule.js

@@ -9,7 +9,7 @@ import {
   makeIDBAvailable,
   setCustomSignals,
 } from '@react-native-firebase/app/lib/internal/web/firebaseRemoteConfig';
-import { guard } from '@react-native-firebase/app/lib/internal/web/utils';
+import { guard, getWebError } from '@react-native-firebase/app/lib/internal/web/utils';
 
 let configSettingsForInstance = {
   // [APP_NAME]: RemoteConfigSettings
@@ -121,4 +121,7 @@ export default {
       return resultAndConstants(remoteConfig, null);
     });
   },
+  onConfigUpdated() {
+    return getWebError('unsupported', 'Not supported by the Firebase Javascript SDK.');
+  },
 };