“txHash: undefined” error using web3.js

Question

Can anyone help me fix this problem? I get 'txHash: undefined' error in terminal

var Tx = require('ethereumjs-tx').Transaction
const Web3 = require('web3')
const web3 = new Web3('https://ropsten.infura.io/.....')

const account1 = '0x4e8143b70aC257BC26......................'
const account2 = '0x7184a5934B9B36E210......................'


const privateKey1 = Buffer.from(process.env.PRIVATE_KEY_1, 'hex')
const privateKey2 = Buffer.from(process.env.PRIVATE_KEY_2, 'hex')

web3.eth.getTransactionCount(account2, (err, txCount) => {

// Build a transaction
const txObject = {
    nonce: web3.utils.toHex(txCount),
    to: account1,
    value: web3.utils.toHex(web3.utils.toWei('1', 'ether')),
    gasLimit: web3.utils.toHex(21000),
    gasPrice: web3.utils.toHex(web3.utils.toWei('10', 'gwei'))
}

// sign a transaction
const tx = new Tx(txObject)
tx.sign(privateKey2)

const serializedTransaction = tx.serialize()
const raw = '0x' + serializedTransaction.toString('hex')

// Broadcast the transacation

web3.eth.sendSignedTransaction(raw, (err, txHash) => {
    console.log('txHash:' , txHash)
})
})

Answer 1

As you are connected to the Ropsten testnet you have to change const tx = new Tx(txObject) to const tx = new Tx(txObject, { chain: 'ropsten' }).

Without the { chain: 'ropsten' }, ethereumjs-tx signs a mainnet transaction. Your code does not work because you are basically trying to send a mainnet transaction whereas your web3 provider connects to the Ropsten testnet.

Note that transaction signatures differ from network to network to protect against replay attacks (see What is a replay attack? for more info).