async function testOrderByPluralIndex(dbName, storeName, sortType) 
{
	const db = await databaseOpen(dbName);
	
	const rows = await runTx(db, storeName, "readonly", (store) => 
	{
		return new Promise((resolve, reject) => {
		const index = store.index("f1_f2");
		const direction = sortType === 0 ? "next" : "prev";
		const result = [];
	
		const req = index.openCursor(null, direction);
		req.onsuccess = (event) => {
			const cursor = event.target.result;
			if (cursor) {
				console.log(cursor.value);
				result.push(cursor.value);
				cursor.continue();
			} 
			else 
			{
				//cursor end
				resolve(result);
			}
		};
		req.onerror = () => reject(req.error);
		});
	});
	
	db.close();
	return rows;
}
function databaseOpen(dbName) 
{
	return new Promise((resolve, reject) => 
	{
		const req = indexedDB.open(dbName);
		req.onsuccess = (event) => 
		{
			resolve(event.target.result);
		};
		req.onerror = () => reject(req.error);
	});
}
function waitForTx(tx) 
{
	return new Promise((resolve, reject) => 
	{
		tx.oncomplete = () => resolve();
		tx.onabort = () => reject(tx.error ?? new Error("Transaction aborted"));
		tx.onerror = () => reject(tx.error);
	});
}

async function runTx(db, storeName, mode, work) 
{
	const tx = db.transaction([storeName], mode);
	const store = tx.objectStore(storeName);
	const result = await work(store);
	await waitForTx(tx);
	return result;
}
//asc
testOrderByPluralIndex("sampleDB", "t2", 0)
.then(rowsAsc => {
	console.log("asc result:", rowsAsc);
})
.catch(error => {
	console.error("asc error:", error);
});

//desc
testOrderByPluralIndex("sampleDB", "t2", 1)
.then(rowsDesc => {
	console.log("desc result:", rowsDesc);
})
.catch(error => {
	console.error("desc error:", error);
});