implement view persistence class to prevent junk subscriptions

src/View/viewPersistence.ts

@@ -0,0 +1,35 @@
+import * as React from "bloatless-react";
+
+class PageTracker {
+    pages: React.State<HTMLElement | undefined> | undefined;
+}
+
+class PageTrackerMap {
+    trackers = new Map<string, PageTracker>();
+
+    private register = (key: string): PageTracker => {
+        if (this.trackers.has(key)) {
+            return this.trackers.get(key);
+        };
+        const tracker = new PageTracker();
+        this.trackers.set(key, tracker);
+        return tracker
+    }
+
+    setPages = (key: string, pages: () => React.State<HTMLElement>): React.State<HTMLElement | undefined> | undefined => {
+        const tracker: PageTracker = this.register(key);
+
+        if (tracker.pages != undefined) {
+            return tracker.pages;
+        } else {
+            tracker.pages = pages();
+            return tracker.pages;
+        }
+    }
+}
+
+export class ViewPersistence {
+    static readonly chatPages = new PageTracker();
+    static readonly taskPages = new PageTrackerMap();
+    static readonly boardPages = new PageTrackerMap();
+}