SheetJS Firebase Dump Demo
Example Code

  /* ... connect to firebase */
  const database = firebase.database();

  /* import workbook */
  await database.ref('foo').set(workbook);

  /* change cells */
  database.ref('foo').update({
    "Sheets/Sheet1/A1": {"t": "s", "v": "J"},
    "Sheets/Sheet1/A2": {"t": "n", "v": 5},
  });

  /* export snapshot */
  const val = await database.ref('foo').once('value').val();
  XLSX.writeFile(wb, "firebase.xlsx");