🏪 Adds a persistent svelte store

app/src/lib/utils.ts

@@ -1,3 +1,5 @@
+import { writable } from 'svelte/store';
+
 export const humanFileSize = (size:number):string => {
     var i = size == 0 ? 0 : Math.floor(Math.log(size) / Math.log(1024));
     return Number((size / Math.pow(1024, i)).toFixed(2)) * 1 + ['B', 'kB', 'MB', 'GB', 'TB'][i];
@@ -5,4 +7,16 @@ export const humanFileSize = (size:number):string => {
 
 export const lerp = (start: number, end: number, amt: number) => {
     return (1 - amt) * start + amt * end;
-};
+};
+
+export const persistentStore = (key:string, initialValue:any) => {
+    const savedValue = JSON.parse(localStorage.getItem(key) as string);
+    const data = savedValue !== null ? savedValue : initialValue;  
+    const store = writable(data);
+    
+    store.subscribe(value => {
+        localStorage.setItem(key, JSON.stringify(value));
+    });
+    
+    return store;
+}