ignore invalid journal entries

src/modules/serverSideStorage.js

@@ -132,7 +132,15 @@ export const _mergeFlags = (recent, stale, allFlagKeys) => {
 }
 
 const _mergeJournal = (...journals) => {
-  const allJournals = flatten(journals.map(j => Array.isArray(j) ? j : []))
+  // Ignore invalid journal entries
+  const allJournals = flatten(
+    journals.map(j => Array.isArray(j) ? j : [])
+  ).filter(entry =>
+    Object.prototype.hasOwnProperty.call(entry, 'path') &&
+    Object.prototype.hasOwnProperty.call(entry, 'operation') &&
+    Object.prototype.hasOwnProperty.call(entry, 'args') &&
+    Object.prototype.hasOwnProperty.call(entry, 'timestamp')
+  )
   const grouped = groupBy(allJournals, 'path')
   const trimmedGrouped = Object.entries(grouped).map(([path, journal]) => {
     // side effect