client/dbOffline: Simplify stats computation

Avoid using stats names from constant since the indirection makes it harder to reason about for both humans and the TypeScript compiler.

Also add a note about the `updateStats` being broken with `itemStatuses` from server since this confused me a bit. For example, if user marks an entry as starred, server will return its unread status as well, and it would increase the statistic. For proper synchronization, we would need journal. Thankfully, the `dbOnline` module passes `updateStats = false`.

Author: jtojnar

client/js/selfoss-db-offline.ts

@@ -16,7 +16,9 @@ export type ItemStatus = {
     starred?: boolean;
 };
 
-const ENTRY_STATUS_NAMES: Array<'unread' | 'starred'> = ['unread', 'starred'];
+function statToNumber(stat: boolean | undefined): number {
+    return stat === undefined ? 0 : stat ? 1 : -1;
+}
 
 export default class DbOffline {
     /** @var Date the datetime of the newest garbage collected entry, i.e. deleted because not of interest. */
@@ -406,15 +408,15 @@ export default class DbOffline {
     }
 
     enqueueStatuses(
-        statuses: { entryId: string; name: string; value: string }[],
+        statuses: { entryId: number; name: string; value: boolean }[],
     ): Promise<void> {
         if (statuses) {
             this.needsSync = true;
         }
 
         const d = new Date();
         const newQueuedStatuses = statuses.map((newStatus) => ({
-            entryId: parseInt(newStatus.entryId),
+            entryId: newStatus.entryId,
             name: newStatus.name,
             value: newStatus.value,
             datetime: d,
@@ -459,6 +461,16 @@ export default class DbOffline {
         return selfoss.dbOnline._syncBegin();
     }
 
+    /**
+     * Update `unread` and `starred` statuses of items in the offline database.
+     *
+     * @param dequee - also clear the local status updates queued to upload to server
+     * @param updateStats - also update local statistics
+     *
+     * Note: Do not use `updateStats` with `itemStatuses` obtained from the server.
+     * The server report cannot distinguish which of the status fields was changed
+     * so both will be considered changed.
+     */
     storeEntryStatuses(
         itemStatuses: ItemStatus[],
         dequeue: boolean = false,
@@ -477,21 +489,21 @@ export default class DbOffline {
 
                     // update entries statuses
                     itemStatuses.forEach((itemStatus) => {
-                        const newStatus = {};
-
-                        ENTRY_STATUS_NAMES.forEach((statusName) => {
-                            if (statusName in itemStatus) {
-                                newStatus[statusName] = itemStatus[statusName];
-
-                                if (updateStats) {
-                                    if (itemStatus[statusName]) {
-                                        statsDiff[statusName]++;
-                                    } else {
-                                        statsDiff[statusName]--;
-                                    }
-                                }
-                            }
-                        });
+                        const newStatus = {
+                            ...('unread' in itemStatus && {
+                                unread: itemStatus.unread,
+                            }),
+                            ...('starred' in itemStatus && {
+                                starred: itemStatus.starred,
+                            }),
+                        };
+
+                        if (updateStats) {
+                            statsDiff.unread += statToNumber(itemStatus.unread);
+                            statsDiff.starred += statToNumber(
+                                itemStatus.starred,
+                            );
+                        }
 
                         const id = itemStatus.id;
                         selfoss.db.storage.entries.get(id).then(