Skip empty field names in Firestore. (#850)

* Fix Vite errors caused by node-fetch.

* Add license header.

* Skip empty field names in Firestore.

* Fix tests.

Author: yuchenshi

src/components/Firestore/DocumentEditor/index.test.tsx

@@ -125,7 +125,7 @@ describe('with basic root fields', () => {
     await act(async () => {
       getByText('add').click();
     });
-    expect(onChange).toHaveBeenCalledWith({ hello: 'world', '': '' });
+    expect(onChange).toHaveBeenCalledWith({ hello: 'world' });
   });
 
   it('removes root-fields', () => {

src/components/Firestore/DocumentEditor/utils.ts

@@ -137,6 +137,10 @@ export function denormalize(store: Store, firestore?: Firestore): FirestoreAny {
   const field = store.fields[store.uuid];
   if (isMapField(field)) {
     return field.mapChildren.reduce((acc, curr) => {
+      if (!curr.name) {
+        // Skip fields with empty name (not allowed by Firestore SDK anyway).
+        return acc;
+      }
       acc[curr.name] = denormalize(
         {
           uuid: curr.valueId,