Need help to run FsAdapter

I have not found any documentation to use FsAdapter.
I try to go thought the lib for help but not get any success.

Code I tried And found Error

const {SBTree, adapters} = require('SBTree');
const fsAdapter = new adapters.FsAdapter();
const tree = new SBTree({adapter: fsAdapter, order:100});

const start = async function () {
  const doc = {_id:'507f1f77bcf86cd799439011',name:"Alex", age:28};
  await tree.insertDocuments(doc);
  const alex = await tree.getDocument("507f1f77bcf86cd799439011");
}
tree.on('ready', start);

Any Help?