// npm install urkel bcrypto

const bcrypto = require('bcrypto');
const random = require('bcrypto/lib/random');
const urkel = require('urkel');
const {BLAKE2b} = bcrypto;
const {randomBytes} = random;
const {Tree, Proof} = urkel;

const dir = process.cwd();

(async () => {
  const tree = new Tree(BLAKE2b, 256, dir);

  await tree.open();
  const txn = tree.transaction();

  const k1 = Buffer.alloc(32);
  const v1 = randomBytes(300);

  const k2 = Buffer.alloc(32);
  k2[31] = 1;
  const v2 = randomBytes(300);

  await txn.insert(k1, v1);
  await txn.insert(k2, v2);

  const root = await txn.commit();
  const snapshot = tree.snapshot(root);

  const proof = await snapshot.prove(k1);
  console.log(proof.nodes.length)
})().catch(err => {
  console.log(err)
});