merkleTree.js

import Web3 from 'web3'
import { whiteList } from './whiteList'

const web3Provider = new Web3.providers.HttpProvider('https://bsc-dataseed1.binance.org:443')
const web3 = new Web3(web3Provider)

const merkleTree = {
  leaves: null,
  root: null
}

function genRootHash() {
  const leaves = genLeaveHashes(whiteList)
  merkleTree.leaves = leaves
  merkleTree.root = buildMerkleTree(leaves)
  console.log('rootHash', merkleTree.root.hash)
  return merkleTree.root.hash
}

function genLeaveHashes(chunks) {
  const leaves = []
  chunks.forEach((data) => {
    const hash = buildHash(data)
    const node = {
      hash,
      parent: null,
    }
    leaves.push(node)
  })
  return leaves
}

function buildMerkleTree(leaves) {
  const numLeaves = leaves.length
  if (numLeaves === 1) {
    return leaves[0]
  }
  const parents = []
  let i = 0
  while (i < numLeaves) {
    const leftChild = leaves[i]
    const rightChild = i + 1 < numLeaves ? leaves[i + 1] : leftChild
    parents.push(createParent(leftChild, rightChild))
    i += 2
  }
  return buildMerkleTree(parents)
}

function createParent(leftChild, rightChild) {
  const hash = leftChild.hash < rightChild.hash ? buildHash(leftChild.hash, rightChild.hash) : buildHash(rightChild.hash, leftChild.hash)
  const parent = {
    hash,
    parent: null,
    leftChild,
    rightChild
  }
  leftChild.parent = parent
  rightChild.parent = parent
  return parent
}

function buildHash(...data) {
  return web3.utils.soliditySha3(...data)
}

function getMerklePath(data) {
  const hash = buildHash(data)
  for (let i = 0; i < merkleTree.leaves.length; i += 1) {
    const leaf = merkleTree.leaves[i]
    if (leaf.hash === hash) {
      return generateMerklePath(leaf)
    }
  }
}

function generateMerklePath(node, path = []) {
  if (node.hash === merkleTree.root.hash) {
    return path
  }
  const isLeft = (node.parent.leftChild === node)
  if (isLeft) {
    path.push(node.parent.rightChild.hash)
  } else {
    path.push(node.parent.leftChild.hash)
  }
  return generateMerklePath(node.parent, path)
}

function verifyPath(data, path) {
  let hash = buildHash(data)
  for (let i = 0; i < path.length; i += 1) {
    hash = hash < path[i] ? buildHash(hash, path[i]) : buildHash(path[i], hash)
  }
  return hash === merkleTree.root.hash
}

export default {
  genRootHash,
  getMerklePath,
  verifyPath
}

whiteList.js

export const whiteList = [
  '0xA1A2EE28Ef70A03864824866b6919c8E6B90c3cD',
  '0xDd1c91fB83412966068E502B289b4AF2eF5362Df',
  '0xd1880fB67cDbB27cE14BC4B1A1f718e308be4aDf',
  '0x2C11506fdc4729914272EB3a5CAf41Ac217Ed2bF',
  '0x0737BEf0f49abCf4A62d480A4fFcE1681f90daEE'
]