fix updatedata

Author: Brian Chen

packages/firestore/src/lite/reference.ts

@@ -76,10 +76,10 @@ export type WithFieldValue<T> = T extends Primitive
  * reference nested fields within the document. FieldValues can be passed in
  * as property values.
  */
-export type UpdateData<T> = T extends Primitive
+export type UpdateData<T> = T extends undefined
+  ? never
+  : T extends Primitive
   ? T
-  : T extends Map<infer K, infer V>
-  ? Map<UpdateData<K>, UpdateData<V>>
   : T extends {}
   ? { [K in keyof T]?: UpdateData<T[K]> | FieldValue } & NestedUpdateFields<T>
   : Partial<T>;

packages/firestore/src/lite/types.ts

@@ -35,7 +35,7 @@ export type NestedUpdateFields<T extends Record<string, unknown>> =
   UnionToIntersection<
     {
       // Check that T[K] extends Record to only allow nesting for map values.
-      [K in keyof T & string]: T[K] extends Record<string, unknown>
+      [K in keyof T & string]: T[K] extends Record<string, unknown> | undefined
         ? // Recurse into the map and add the prefix in front of each key
           // (e.g. Prefix 'bar.' to create: 'bar.baz' and 'bar.qux'.
           AddPrefixToKeys<K, UpdateData<T[K]>>

packages/firestore/test/lite/integration.test.ts

@@ -1542,6 +1542,49 @@ describe('withConverter() support', () => {
         });
       });
 
+      it('supports optional fields', () => {
+        interface TestObjectOptional {
+          optionalStr?: string;
+          nested?: {
+            requiredStr: string;
+          };
+        }
+
+        const testConverterOptional = {
+          toFirestore(testObj: WithFieldValue<TestObjectOptional>) {
+            return { ...testObj };
+          },
+          fromFirestore(snapshot: QueryDocumentSnapshot): TestObjectOptional {
+            const data = snapshot.data();
+            return {
+              optionalStr: data.optionalStr,
+              nested: data.nested
+            };
+          }
+        };
+
+        return withTestDocAndInitialData(initialData, async docRef => {
+          const testDocRef: DocumentReference<TestObjectOptional> =
+            docRef.withConverter(testConverterOptional);
+
+          await updateDoc(testDocRef, {
+            optionalStr: 'foo'
+          });
+          await updateDoc(testDocRef, {
+            'optionalStr': 'foo'
+          });
+
+          await updateDoc(testDocRef, {
+            nested: {
+              requiredStr: 'foo'
+            }
+          });
+          await updateDoc(testDocRef, {
+            'nested.requiredStr': 'foo'
+          });
+        });
+      });
+
       it('checks for nonexistent fields', () => {
         return withTestDocAndInitialData(initialData, async docRef => {
           const testDocRef: DocumentReference<TestObject> =