[internals][types] Last part of internal refactor; Got rid of remaining flow errors

lib/modules/firestore/Query.js

@@ -8,6 +8,7 @@ import { buildNativeArray, buildTypeMap } from './utils/serialize';
 import { getAppEventName, SharedEventEmitter } from '../../utils/events';
 import { getLogger } from '../../utils/log';
 import { firestoreAutoId, isFunction, isObject } from '../../utils';
+import { getNativeModule } from '../../utils/native';
 
 import type Firestore from './';
 import type { FirestoreQueryDirection, FirestoreQueryOperator } from '../../types';
@@ -53,9 +54,12 @@ export type QueryListenOptions = {
   includeQueryMetadataChanges: boolean,
 }
 
+export type ObserverOnError = (Object) => void;
+export type ObserverOnNext = (QuerySnapshot) => void;
+
 export type Observer = {
-  next: (DocumentSnapshot) => void,
-  error?: (Object) => void,
+  error?: ObserverOnError,
+  next: ObserverOnNext,
 }
 
 /**
@@ -119,7 +123,7 @@ export default class Query {
   }
 
   get(): Promise<QuerySnapshot> {
-    return this._firestore._native
+    return getNativeModule(this._firestore)
       .collectionGet(
         this._referencePath.relativeName,
         this._fieldFilters,
@@ -147,19 +151,22 @@ export default class Query {
   }
 
   onSnapshot(
-    optionsOrObserverOrOnNext: QueryListenOptions | Observer | (DocumentSnapshot) => void,
-    observerOrOnNextOrOnError?: Observer | (DocumentSnapshot) => void | (Object) => void,
-    onError?: (Object) => void,
+    optionsOrObserverOrOnNext: QueryListenOptions | Observer | ObserverOnNext,
+    observerOrOnNextOrOnError?: Observer | ObserverOnNext | ObserverOnError,
+    onError?: ObserverOnError,
   ) {
-    let observer = {};
+    let observer: Observer;
     let queryListenOptions = {};
     // Called with: onNext, ?onError
     if (isFunction(optionsOrObserverOrOnNext)) {
-      observer.next = optionsOrObserverOrOnNext;
       if (observerOrOnNextOrOnError && !isFunction(observerOrOnNextOrOnError)) {
         throw new Error('Query.onSnapshot failed: Second argument must be a valid function.');
       }
-      observer.error = observerOrOnNextOrOnError;
+      // $FlowBug: Not coping with the overloaded method signature
+      observer = {
+        next: optionsOrObserverOrOnNext,
+        error: observerOrOnNextOrOnError,
+      };
     } else if (optionsOrObserverOrOnNext && isObject(optionsOrObserverOrOnNext)) {
       // Called with: Observer
       if (optionsOrObserverOrOnNext.next) {
@@ -167,7 +174,11 @@ export default class Query {
           if (optionsOrObserverOrOnNext.error && !isFunction(optionsOrObserverOrOnNext.error)) {
             throw new Error('Query.onSnapshot failed: Observer.error must be a valid function.');
           }
-          observer = optionsOrObserverOrOnNext;
+          // $FlowBug: Not coping with the overloaded method signature
+          observer = {
+            next: optionsOrObserverOrOnNext.next,
+            error: optionsOrObserverOrOnNext.error,
+          };
         } else {
           throw new Error('Query.onSnapshot failed: Observer.next must be a valid function.');
         }
@@ -175,18 +186,24 @@ export default class Query {
         queryListenOptions = optionsOrObserverOrOnNext;
         // Called with: Options, onNext, ?onError
         if (isFunction(observerOrOnNextOrOnError)) {
-          observer.next = observerOrOnNextOrOnError;
           if (onError && !isFunction(onError)) {
             throw new Error('Query.onSnapshot failed: Third argument must be a valid function.');
           }
-          observer.error = onError;
+          // $FlowBug: Not coping with the overloaded method signature
+          observer = {
+            next: observerOrOnNextOrOnError,
+            error: onError,
+          };
         // Called with Options, Observer
         } else if (observerOrOnNextOrOnError && isObject(observerOrOnNextOrOnError) && observerOrOnNextOrOnError.next) {
           if (isFunction(observerOrOnNextOrOnError.next)) {
             if (observerOrOnNextOrOnError.error && !isFunction(observerOrOnNextOrOnError.error)) {
               throw new Error('Query.onSnapshot failed: Observer.error must be a valid function.');
             }
-            observer = observerOrOnNextOrOnError;
+            observer = {
+              next: observerOrOnNextOrOnError.next,
+              error: observerOrOnNextOrOnError.error,
+            };
           } else {
             throw new Error('Query.onSnapshot failed: Observer.next must be a valid function.');
           }
@@ -199,7 +216,6 @@ export default class Query {
     } else {
       throw new Error('Query.onSnapshot failed: Called with invalid arguments.');
     }
-
     const listenerId = firestoreAutoId();
 
     const listener = (nativeQuerySnapshot) => {
@@ -222,7 +238,7 @@ export default class Query {
     }
 
     // Add the native listener
-    this._firestore._native
+    getNativeModule(this._firestore)
       .collectionOnSnapshot(
         this._referencePath.relativeName,
         this._fieldFilters,
@@ -339,7 +355,7 @@ export default class Query {
     getLogger(this._firestore).info('Removing onQuerySnapshot listener');
     SharedEventEmitter.removeListener(getAppEventName(this._firestore, `onQuerySnapshot:${listenerId}`), listener);
     SharedEventEmitter.removeListener(getAppEventName(this._firestore, `onQuerySnapshotError:${listenerId}`), listener);
-    this._firestore._native
+    getNativeModule(this._firestore)
       .collectionOffSnapshot(
         this._referencePath.relativeName,
         this._fieldFilters,