Cleanup, progress storing and settings handling

src/lib/settings/progress.ts

@@ -0,0 +1,25 @@
+import { browser } from "$app/environment";
+import { writable } from "svelte/store";
+
+type Progress = Record<string, number> | undefined
+
+const stored = browser ? window.localStorage.getItem('progress') : undefined
+const initial: Progress = stored && browser ? JSON.parse(stored) : undefined
+
+export const progress = writable<Progress>(initial);
+
+export function updateProgress(volume: string, value: number) {
+  progress.update((prev) => {
+    return {
+      ...prev,
+      [volume]: value
+    };
+  });
+}
+
+progress.subscribe((progress) => {
+  if (browser) {
+    window.localStorage.setItem('progress', JSON.stringify(progress))
+  }
+})
+