How use function database().on() asynchronously?

[xDavidos]

Hello guys, I have the next problem:

export async function updateLessons() { 
  let data
  await database().goOnline().then(async () => {
    await database()
    .ref('days')
    .on('value', snapshot => {
      console.log(snapshot.val())
      data = snapshot.val();
    });
  });

  return data;
}

I use this function to update my application when I swipe down

  const onRefresh = React.useCallback(async () => {
    setRefreshing(true);
    setLessons(await updateLessons());
    console.log(lessons)
    setRefreshing(false);
  }, []);

It is called from scroll view (refreshcontrol)
The problem is that it doesn't work synchronously. In console log i see my snapshot. But the application updated faster and in console.log(lessons) it is undefined. How can I fix it?
I want the first time the application was launched with the Internet, I want the data to be downloaded from the data, but if there is no access to the Internet, null returns. But all the recent discoveries of the application without access to the Internet, the data was downloaded from the locale, but if there is an Internet connection and there is a change in the dates, these were updated. Also, when swipe at the bottom to data try to update, if there is no Internet then the local data return.

[xDavidos]

Already done