Transaction createion example without web3

import util from 'ethereumjs-util';
import Tx from 'ethereumjs-tx';
const toHex = number => '0x' +  number.toString(16);

const privateKey = '0x4e568ee4ade234cec266d158c3f5ab23985058a4a9157d84f802ee23c3af0c89';
console.log('Private key ', privateKey);

const publicKeyBuffer = util.privateToPublic(util.toBuffer(privateKey));
const publicKey = util.bufferToHex(publicKeyBuffer);
console.log('Public key ', publicKey);

const address = '0x' + util.bufferToHex(util.keccak256(publicKeyBuffer)).slice(26);
console.log('Address ', address);

const rawTx = {
    nonce: toHex(0),
    gasPrice: toHex(20000000000),
    gasLimit: toHex(100000),
    to: '0xecA0A3eFCf009519052Dc92306fE821b9c7A32A2',
    value: toHex(1000),
    data: util.bufferToHex(Buffer.from('Hello world!', 'utf8'))
};

const p = Buffer.from(privateKey.slice(2), 'hex');
const transaction = new Tx.Transaction(rawTx, { chain: 'kovan', hardfork: 'petersburg' });
console.log('Raw transaction ', util.bufferToHex(transaction.serialize()));

transaction.sign(p);
const serializedTx = transaction.serialize()

console.log('Signed transaction ', util.bufferToHex(serializedTx));