First version of Karten App

src/adapters/marks-db.ts

@@ -0,0 +1,57 @@
+import type { MarksPort } from "../karte/types";
+
+const DB_NAME = "karte";
+const STORE = "marks";
+const KEY = "heruntergeladen";
+
+function openDatabase(): Promise<IDBDatabase> {
+  return new Promise((resolve, reject) => {
+    const request = indexedDB.open(DB_NAME, 1);
+    request.onupgradeneeded = () => {
+      const db = request.result;
+      if (!db.objectStoreNames.contains(STORE)) db.createObjectStore(STORE);
+    };
+    request.onsuccess = () => resolve(request.result);
+    request.onerror = () => reject(request.error ?? new Error("IndexedDB"));
+  });
+}
+
+function stringsFrom(value: unknown): string[] {
+  if (!Array.isArray(value)) return [];
+  return value.filter((item): item is string => typeof item === "string");
+}
+
+function settle(tx: IDBTransaction, value: () => unknown): Promise<unknown> {
+  return new Promise((resolve, reject) => {
+    tx.oncomplete = () => resolve(value());
+    tx.onerror = () => reject(tx.error ?? new Error("IndexedDB"));
+    tx.onabort = () => reject(tx.error ?? new Error("IndexedDB"));
+  });
+}
+
+export function createMarksDb(): MarksPort {
+  return {
+    async read() {
+      const db = await openDatabase();
+      try {
+        const tx = db.transaction(STORE, "readonly");
+        const request = tx.objectStore(STORE).get(KEY);
+        const value = await settle(tx, () => request.result);
+        return { heruntergeladen: stringsFrom(value) };
+      } finally {
+        db.close();
+      }
+    },
+
+    async write(state) {
+      const db = await openDatabase();
+      try {
+        const tx = db.transaction(STORE, "readwrite");
+        tx.objectStore(STORE).put(state.heruntergeladen, KEY);
+        await settle(tx, () => undefined);
+      } finally {
+        db.close();
+      }
+    },
+  };
+}