feat: returns undefined on initial read when in-memory db is empty

feat: returns undefined on initial read when in-memory db is empty

Author: Bobby

src/actions/firestore.js

@@ -97,6 +97,10 @@ export function get(firebase, dispatch, queryOption) {
         payload: (snap) => ({
           data: dataByIdSnapshot(snap),
           ordered: orderedFromSnap(snap),
+          fromCache:
+            typeof snap.metadata?.fromCache === 'boolean'
+              ? snap.metadata.fromCache
+              : true,
         }),
         merge: {
           docs: mergeOrdered && mergeOrderedDocUpdates,

src/reducers/cacheReducer.js

@@ -105,7 +105,7 @@ const PROCESSES = {
   '>=': (a, b) => a >= b,
   '>': (a, b) => a > b,
   'array-contains': (a, b) => a.includes(b),
-  in: (a, b) => a && a.includes(b),
+  in: (a, b) => a && b && b.includes(a),
   'array-contains-any': (a, b) => b.some((b1) => a.includes(b1)),
   'not-in': (a, b) => !b.includes(a),
   '*': () => true,
@@ -369,7 +369,8 @@ function reprocessQuerires(draft, path) {
 
     const docs = selectDocuments(draft, draft[key]);
     const ordered = docs.map(({ id, path: _path }) => [_path, id]);
-    set(draft, [key, 'docs'], docs);
+    const isInitialLoad = draft[key].via === 'memory' && docs.length === 0;
+    set(draft, [key, 'docs'], isInitialLoad ? undefined : docs);
     set(draft, [key, 'ordered'], ordered);
   });
 
@@ -557,6 +558,12 @@ const initialize = (state, { action, key, path }) =>
       set(draft, ['databaseOverrides'], {});
     }
 
+    const via = {
+      undefined: 'memory',
+      true: 'cache',
+      false: 'server',
+    }[action.payload.fromCache];
+
     if (action.payload.data) {
       Object.keys(action.payload.data).forEach((id) => {
         setWith(draft, ['database', path, id], action.payload.data[id], Object);
@@ -569,9 +576,11 @@ const initialize = (state, { action, key, path }) =>
     const ordered = (
       action.payload.ordered || selectDocuments(draft, action.meta)
     ).map(({ path, id }) => [path, id]);
+
     set(draft, [action.meta.storeAs], {
       ordered,
       ...action.meta,
+      via,
     });
 
     // append docs field to query
@@ -778,9 +787,9 @@ const mutation = (state, { action, key, path }) =>
   });
 
 const HANDLERS = {
-  [actionTypes.GET_SUCCESS]: initialize,
-  [actionTypes.LISTENER_RESPONSE]: initialize,
   [actionTypes.SET_LISTENER]: initialize,
+  [actionTypes.LISTENER_RESPONSE]: initialize,
+  [actionTypes.GET_SUCCESS]: initialize,
   [actionTypes.UNSET_LISTENER]: conclude,
   [actionTypes.DOCUMENT_ADDED]: modify,
   [actionTypes.DOCUMENT_MODIFIED]: modify,

src/utils/query.js

@@ -791,6 +791,10 @@ export function dispatchListenerResponse({
     mergeOrderedDocUpdates,
     mergeOrderedCollectionUpdates,
   } = firebase._.config || {};
+  const fromCache =
+    typeof docData.metadata?.fromCache === 'boolean'
+      ? docData.metadata.fromCache
+      : true;
   const docChanges =
     typeof docData.docChanges === 'function'
       ? docData.docChanges()
@@ -810,6 +814,7 @@ export function dispatchListenerResponse({
       payload: {
         data: dataByIdSnapshot(docData),
         ordered: orderedFromSnap(docData),
+        fromCache,
       },
       merge: {
         docs: mergeOrdered && mergeOrderedDocUpdates,

test/unit/actions/firestore.spec.js

@@ -463,7 +463,7 @@ describe('firestoreActions', () => {
             };
             const expectedAction2 = {
               meta: listenerConfig,
-              payload: { data: null, ordered: [] },
+              payload: { data: null, ordered: [], fromCache: true },
               merge: { collections: true, docs: true },
               type: actionTypes.LISTENER_RESPONSE,
             };
@@ -644,7 +644,7 @@ describe('firestoreActions', () => {
             };
             const expectedAction2 = {
               meta: listenerConfig,
-              payload: { data: null, ordered: [] },
+              payload: { data: null, ordered: [], fromCache: true },
               merge: { collections: true, docs: true },
               type: actionTypes.LISTENER_RESPONSE,
             };