//sortType:[0]asc [1]desc
async function testOrderBy(dbName, storeName, sortType) 
{
	const db = await databaseOpen(dbName);
	await runTx(db, storeName, "readwrite", (store) => 
	{

		// get cursor data
		const transaction = db.transaction([storeName], 'readonly');
		const objectStore = transaction.objectStore(storeName);
		const index = objectStore.index('f1'); //use "f1" index
		
		const cursorRequest = index.openCursor(null, sortType == 0 ? "next" : "prev");
		cursorRequest.onsuccess = (event) => 
		{
			const cursor = event.target.result;
			if (cursor) 
			{
				console.log(cursor.value); //display sort cursor data
				cursor.continue();
			} 
			else 
			{
				console.log('get all of data.');
			}
		};

	});
	db.close();
}
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;
}
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);
	});
}
testOrderBy("sampleDB", "t2", 0);
console.log("-----");
testOrderBy("sampleDB", "t2", 1);