WIP: use indexedDB as datastore for geotiles

Logic/Web/IdbLocalStorage.ts

@@ -0,0 +1,25 @@
+import {UIEventSource} from "../UIEventSource";
+import * as idb from "idb-keyval"
+/**
+ * UIEventsource-wrapper around indexedDB key-value
+ */
+export class IdbLocalStorage {
+
+    
+    public static Get<T>(key: string, options: { defaultValue?: T }): UIEventSource<T>{
+        const src = new UIEventSource<T>(options.defaultValue, "idb-local-storage:"+key)
+        idb.get(key).then(v => {
+            src.setData(v ?? options.defaultValue)
+        })
+        src.stabilized(1000).addCallback(v => {
+            idb.set(key, v)
+        })
+        return src;
+        
+    }
+    
+    public static SetDirectly(key: string, value){
+        idb.set(key, value)
+    }
+
+}