const bdb = require('bdb');

const db = bdb.create({
  location: './mydb'
});

await db.open();

const root = bdb.key('r');
const rec = bdb.key('t', ['hash160', 'uint32']);

const bucket = db.bucket(root.build());
const batch = bucket.batch();

const hash = Buffer.alloc(20, 0x11);

// Write `foo` to `rt[1111111111111111111111111111111111111111][00000000]`.
batch.put(rec.build(hash, 0), Buffer.from('foo'));

await batch.write();

// Iterate:
// From: `rt[0000000000000000000000000000000000000000][00000000]`
// To: `rt[ffffffffffffffffffffffffffffffffffffffff][ffffffff]`
const iter = bucket.iterator({
  gte: rec.min(),
  lte: rec.max(),
  values: true
});

await iter.each((key, value) => {
  // Parse each key.
  const [hash, uint] = rec.parse(key);
  console.log('Hash: %s', hash);
  console.log('Uint: %d', uint);
  console.log('Value: %s', value.toString('ascii'));
});

await db.close();