Feature: stabilize saved history, add code to cleanup old preferences, make loading preferences faster (which prevents a 'hang') when just logged in

src/Logic/Osm/OsmConnection.ts

@@ -246,11 +246,13 @@ export class OsmConnection {
     }
 
     public getPreference<T extends string = string>(
-        key: string,
-        defaultValue: string = undefined,
-        prefix: string = "mapcomplete-"
+        key: string, options?: {
+            defaultValue?: string,
+            prefix?: "mapcomplete-" | string,
+            saveToLocalStorage?: true | boolean
+        }
     ): UIEventSource<T | undefined> {
-        return <UIEventSource<T>>this.preferencesHandler.getPreference(key, defaultValue, prefix)
+        return <UIEventSource<T>>this.preferencesHandler.getPreference(key, options?.defaultValue, options?.prefix ?? "mapcomplete-")
     }
 
     public LogOut() {
@@ -731,4 +733,24 @@ export class OsmConnection {
             return { api: "offline", gpx: "offline", database: "online" }
         }
     }
+
+    public getCurrentChangesetFor(theme: string) {
+        return UIEventSource.asObject<{ id: number, opened: number }>(
+            this.GetPreference(
+                "current-changeset-" + theme
+            ),
+            undefined
+        )
+    }
+
+    /**
+     * Returns the names of the themes that have an open changeset
+     */
+    public getAllOpenChangesetsPreferences(): Store<string[]> {
+        const prefix = "current-changeset-"
+        return this.preferencesHandler.allPreferences.map(dict =>
+            Object.keys(dict)
+                .filter(k => k.startsWith(prefix))
+                .map(k => k.substring(prefix.length)))
+    }
 }