Simple Patricia Trie what showed in "Patricia Trie" in Ethereum wiki.

patricia_sampl_dump.js

const BaseTrie = require('merkle-patricia-tree/baseTrie')
const TrieNode = require('merkle-patricia-tree/trieNode')

const toNibbleArray = (bytes) => {
  let nibbles = []
  bytes.forEach((b) => {
    nibbles.push(parseInt(b / 16))
    nibbles.push(b % 16)
  })
  return Buffer.from(nibbles)
}

// ######################################################
// ######################################################
// ### Create simple trie what showed in sample.   ######
// ######################################################
// ######################################################
async function SampleTrie() {
  const putAsync = (trie, key, value) => {
    return new Promise((resolve, reject) => {
      trie.put(key, value, (err) => {
        if(err) {
          reject(err)
        } else {
          resolve()
        }
      })
    })
  }
  const trie = new BaseTrie()
  await putAsync(trie, "do", "verb")
  await putAsync(trie, "dog", "puppy")
  await putAsync(trie, "doge", "coin")
  await putAsync(trie, "horse", "stallion")

  const dump = (node) => {
    let res = "["+ node.hash().toString("hex") +"] "
    if (node.type === 'leaf') {
      res += node.type + ": "
      res += node.raw[0].toString("hex") + "=" + node.raw[1].toString()
    } else if(node.type === 'branch') {
      res += node.type + ": "
      node.raw.forEach((b,i) => {
        let node_hash = ""
        if(b instanceof Buffer && b.length > 0) {
          node_hash = b.toString("hex")
          if(i === 16) {
            node_hash = b.toString()
          }
        } else if(b instanceof Array) {
          node_hash = new TrieNode(b).hash().toString("hex")
        }
        res += "<" + node_hash + ">, "
      })
    } else {
      res += node.type + ": "
      let value = node.raw[1].toString("hex")
      if(node.raw[1] instanceof Array) {
        value = new TrieNode(node.raw[1]).hash().toString("hex")
      }
      res += node.raw[0].toString("hex") + "=" + value
    }

    return res
  }
  trie._walkTrie(trie.root, function (nodeRef, node, key, walkController) {
    console.log(dump(node))
    walkController.next();
  })
}

SampleTrie().then()