@ethereumjs/tx

Note: this README reflects the state of the library from v3.0.0 onwards. See README from the standalone repository for an introduction on the last preceding release.

Installation

General

To obtain the latest version, simply require the project using npm:

npm install @ethereumjs/tx

KZG Setup

This library supports an experimental version of EIP-4844 blob transactions (see usage instructions below) starting with v4.1.0.

For blob transactions and other KZG related proof functionality (e.g. for EVM precompiles) KZG has to be manually installed and initialized once in a global scope. The functionality is then available for all KZG usages throughout different libraries (Transaction, Block, EVM).

Manual Installation

The following two manual installation steps for a KZG library and the trusted setup are needed.

1. Install an additional dependency that supports the kzg interface defined in the kzg interface. You can install the default option c-kzg by simply running npm install c-kzg.
2. Download the trusted setup required for the KZG module. It can be found here within the client package.

Global Initialization

Global initialization can then be done like this (using the c-kzg module for our KZG dependency):

// Make the kzg library available globally
import * as kzg from 'c-kzg'

// Initialize the trusted setup
initKZG(kzg, 'path/to/my/trusted_setup.txt')

Usage

Static Constructor Methods

To instantiate a tx it is not recommended to use the constructor directly. Instead each tx type comes with the following set of static constructor methods which helps on instantiation depending on the input data format:

• public static fromTxData(txData: TxData, opts: TxOptions = {}): instantiate from a data dictionary
• public static fromSerializedTx(serialized: Buffer, opts: TxOptions = {}): instantiate from a serialized tx
• public static fromValuesArray(values: Buffer[], opts: TxOptions = {}): instantiate from a values array

See one of the code examples on the tx types below on how to use.

All types of transaction objects are frozen with Object.freeze() which gives you enhanced security and consistency properties when working with the instantiated object. This behavior can be modified using the freeze option in the constructor if needed.

Chain and Hardfork Support

The Transaction constructor receives a parameter of an @ethereumjs/common object that lets you specify the chain and hardfork to be used. If there is no Common provided the chain ID provided as a parameter on typed tx or the chain ID derived from the v value on signed EIP-155 conforming legacy txs will be taken (introduced in v3.2.1). In other cases the chain defaults to mainnet.

Base default HF (determined by Common): merge

Starting with v3.2.1 the tx library now deviates from the default HF for typed tx using the following rule: "The default HF is the default HF from Common if the tx type is active on that HF. Otherwise it is set to the first greater HF where the tx is active."

Hardforks adding features and/or tx types:

Standalone EIPs

The following "standalone" EIPs are supported by the library can be manually activated using a respectively initialized Common instance, e.g.:

const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.London, eips: [3860] })

• EIP-3860: Limit and meter initcode (experimental)

Transaction Types

This library supports the following transaction types (EIP-2718):

• BlobEIP4844Transaction (EIP-4844, proto-danksharding)
• FeeMarketEIP1559Transaction (EIP-1559, gas fee market)
• AccessListEIP2930Transaction (EIP-2930, optional access lists)
• Transaction, the Ethereum standard tx up to berlin, now referred to as legacy txs with the introduction of tx types

Blob Transactions (EIP-4844)

• Class: BlobEIP4844Transaction
• Activation: sharding
• Type: 5

This library supports an experimental version of the blob transaction type introduced with EIP-4844 as being specified in the 01d3209 EIP version from February 8, 2023 and deployed along eip4844-devnet-4 (January 2023), see PR #2349.

Note: This functionality needs a manual KZG library installation and global initialization, see KZG Setup for instructions.

Usage

See the following code snipped for an example on how to instantiate (using the c-kzg module for our KZG dependency).

import { Chain, Common, Hardfork } from 'ethereumjs-fork-common'
import { BlobEIP4844Transaction, initKZG } from '@ethereumjs/tx'
import * as kzg from 'c-kzg'

initKZG(kzg, 'path/to/my/trusted_setup.txt')
const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.Shanghai, eips: [4844] })

const txData = {
  data: '0x1a8451e600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000',
  gasLimit: '0x02625a00',
  maxPriorityFeePerGas: '0x01',
  maxFeePerGas: '0xff',
  maxFeePerDataGas: '0xfff',
  nonce: '0x00',
  to: '0xcccccccccccccccccccccccccccccccccccccccc',
  value: '0x0186a0',
  v: '0x01',
  r: '0xafb6e247b1c490e284053c87ab5f6b59e219d51f743f7a4d83e400782bc7e4b9',
  s: '0x479a268e0e0acd4de3f1e28e4fac2a6b32a4195e8dfa9d19147abe8807aa6f64',
  chainId: '0x01',
  accessList: [],
  type: '0x05',
  versionedHashes: ['0xabc...'], // Test with empty array on a first run
  kzgCommitments: ['0xdef...'], // Test with empty array on a first run
  blobs: ['0xghi...'], // Test with empty array on a first run
}

const tx = BlobEIP4844Transaction.fromTxData(txData, { common })

Note that versionedHashes and kzgCommitments have a real length of 32 bytes and blobs have a real length of 4096 bytes and values are trimmed here for brevity.

See the Blob Transaction Tests for examples of usage in instantiating, serializing, and deserializing these transactions.

Gas Fee Market Transactions (EIP-1559)

• Class: FeeMarketEIP1559Transaction
• Activation: london
• Type: 2

This is the recommended tx type starting with the activation of the london HF, see the following code snipped for an example on how to instantiate:

import { Chain, Common, Hardfork } from 'ethereumjs-fork-common'
import { FeeMarketEIP1559Transaction } from '@ethereumjs/tx'

const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.London })

const txData = {
  data: '0x1a8451e600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000',
  gasLimit: '0x02625a00',
  maxPriorityFeePerGas: '0x01',
  maxFeePerGas: '0xff',
  nonce: '0x00',
  to: '0xcccccccccccccccccccccccccccccccccccccccc',
  value: '0x0186a0',
  v: '0x01',
  r: '0xafb6e247b1c490e284053c87ab5f6b59e219d51f743f7a4d83e400782bc7e4b9',
  s: '0x479a268e0e0acd4de3f1e28e4fac2a6b32a4195e8dfa9d19147abe8807aa6f64',
  chainId: '0x01',
  accessList: [],
  type: '0x02',
}

const tx = FeeMarketEIP1559Transaction.fromTxData(txData, { common })

Access List Transactions (EIP-2930)

• Class: AccessListEIP2930Transaction
• Activation: berlin
• Type: 1

This transaction type has been introduced along the berlin HF. See the following code snipped for an example on how to instantiate:

import { Chain, Common, Hardfork } from 'ethereumjs-fork-common'
import { AccessListEIP2930Transaction } from '@ethereumjs/tx'

const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.Berlin })

const txData = {
  data: '0x1a8451e600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000',
  gasLimit: '0x02625a00',
  gasPrice: '0x01',
  nonce: '0x00',
  to: '0xcccccccccccccccccccccccccccccccccccccccc',
  value: '0x0186a0',
  v: '0x01',
  r: '0xafb6e247b1c490e284053c87ab5f6b59e219d51f743f7a4d83e400782bc7e4b9',
  s: '0x479a268e0e0acd4de3f1e28e4fac2a6b32a4195e8dfa9d19147abe8807aa6f64',
  chainId: '0x01',
  accessList: [
    {
      address: '0x0000000000000000000000000000000000000101',
      storageKeys: [
        '0x0000000000000000000000000000000000000000000000000000000000000000',
        '0x00000000000000000000000000000000000000000000000000000000000060a7',
      ],
    },
  ],
  type: '0x01',
}

const tx = AccessListEIP2930Transaction.fromTxData(txData, { common })

For generating access lists from tx data based on a certain network state there is a reportAccessList option on the Vm.runTx() method of the @ethereumjs/vm TypeScript VM implementation.

Legacy Transactions

• Class: Transaction
• Activation: chainstart (with modifications along the road, see HF section below)
• Type: 0 (internal)

Legacy transaction are still valid transaction within Ethereum mainnet but will likely be deprecated at some point. See this example script or the following code example on how to use.

import { Chain, Common, Hardfork } from 'ethereumjs-fork-common'
import { Transaction } from '@ethereumjs/tx'

const txParams = {
  nonce: '0x00',
  gasPrice: '0x09184e72a000',
  gasLimit: '0x2710',
  to: '0x0000000000000000000000000000000000000000',
  value: '0x00',
  data: '0x7f7465737432000000000000000000000000000000000000000000000000000000600057',
}

const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.Istanbul })
const tx = Transaction.fromTxData(txParams, { common })

const privateKey = Buffer.from(
  'e331b6d69882b4cb4ea581d88e0b604039a3de5967688d3dcffdd2270c0fd109',
  'hex'
)

const signedTx = tx.sign(privateKey)

const serializedTx = signedTx.serialize()

Transaction Factory

If you only know on runtime which tx type will be used within your code or if you want to keep your code transparent to tx types, this library comes with a TransactionFactory for your convenience which can be used as follows:

import { Chain, Common, Hardfork } from 'ethereumjs-fork-common'
import { TransactionFactory } from '@ethereumjs/tx'

const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.Berlin })

const txData = {} // Use data from the different tx type examples
const tx = TransactionFactory.fromTxData(txData, { common })

if (tx.supports(Capability.EIP2930AccessLists)) {
  // Do something which only makes sense for txs with support for access lists
}

The correct tx type class for instantiation will then be chosen on runtime based on the data provided as an input.

TransactionFactory supports the following static constructor methods:

• public static fromTxData(txData: TxData | AccessListEIP2930TxData, txOptions: TxOptions = {}): TypedTransaction
• public static fromSerializedData(data: Buffer, txOptions: TxOptions = {}): TypedTransaction
• public static fromBlockBodyData(data: Buffer | Buffer[], txOptions: TxOptions = {})
• public static async fromEthersProvider(provider: string | ethers.providers.JsonRpcProvider, txHash: string, txOptions?: TxOptions)

Sending a Transaction

L2 Support

This library has been tested to work with various L2 networks (v3.3.0+). All predefined supported custom chains introduced with Common v2.4.0 or higher are supported, the following is a simple example to send a tx to the xDai chain:

import { Transaction } from '@ethereumjs/tx'
import { Common } from 'ethereumjs-fork-common'

const from = 'PUBLIC_KEY'
const PRIV_KEY = process.argv[2]
const to = 'DESTINATION_ETHEREUM_ADDRESS'

const common = Common.custom(CustomChain.xDaiChain)

const txData = {
  from,
  nonce: 0,
  gasPrice: 1000000000,
  gasLimit: 21000,
  to,
  value: 1,
}

const tx = Transaction.fromTxData(txData, { common })
const signedTx = tx.sign(Buffer.from(PRIV_KEY, 'hex'))

The following L2 networks have been tested to work with @ethereumjs/tx, see usage examples as well as some notes on peculiarities in the issues linked below:

Note: For Optimistic Kovan and Optimistic Ethereum, the London hardfork has not been implemented so transactions submitted with a baseFee will revert. The London hardfork is targeted to implement on Optimism in Q1.22.

For a non-predefined custom chain it is also possible to just provide a chain ID as well as other parameters to Common:

const common = Common.custom({ chainId: 1234 })

Special Topics

Signing with a hardware or external wallet

To sign a tx with a hardware or external wallet use tx.getMessageToSign(false) to return an EIP-155 compliant unsigned tx.

A legacy transaction will return a Buffer list of the values, and a Typed Transaction (EIP-2718) will return the serialized output.

Here is an example of signing txs with @ledgerhq/hw-app-eth as of v6.5.0:

import { Transaction, FeeMarketEIP1559Transaction } from '@ethereumjs/tx'
import { Chain, Common } from 'ethereumjs-fork-common'
import { bufArrToArr } from '@ethereumjs/util'
import { RLP } from '@ethereumjs/rlp'
import Eth from '@ledgerhq/hw-app-eth'

const eth = new Eth(transport)
const common = new Common({ chain: Chain.Rinkeby })

let txData: any = { value: 1 }
let tx: Transaction | FeeMarketEIP1559Transaction
let unsignedTx: Buffer[] | Buffer
let signedTx: typeof tx
const bip32Path = "44'/60'/0'/0/0"

const run = async () => {
  // Signing a legacy tx
  tx = Transaction.fromTxData(txData, { common })
  unsignedTx = tx.getMessageToSign(false)
  unsignedTx = Buffer.from(RLP.encode(bufArrToArr(unsignedTx))) // ledger signTransaction API expects it to be serialized
  let { v, r, s } = await eth.signTransaction(bip32Path, unsignedTx)
  txData = { ...txData, v, r, s }
  signedTx = Transaction.fromTxData(txData, { common })
  let from = signedTx.getSenderAddress().toString()
  console.log(`signedTx: 0x${signedTx.serialize().toString('hex')}\nfrom: ${from}`)

  // Signing a 1559 tx
  txData = { value: 1 }
  tx = FeeMarketEIP1559Transaction.fromTxData(txData, { common })
  unsignedTx = tx.getMessageToSign(false)
  ;({ v, r, s } = await eth.signTransaction(bip32Path, unsignedTx)) // this syntax is: object destructuring - assignment without declaration
  txData = { ...txData, v, r, s }
  signedTx = FeeMarketEIP1559Transaction.fromTxData(txData, { common })
  from = signedTx.getSenderAddress().toString()
  console.log(`signedTx: ${signedTx.serialize().toString('hex')}\nfrom: ${from}`)
}

run()

Fake Transaction

Creating a fake transaction for use in e.g. VM.runTx() is simple, just overwrite getSenderAddress() with a custom Address like so:

import { Address } from '@ethereumjs/util'
import { Transaction } from '@ethereumjs/tx'

_getFakeTransaction(txParams: TxParams): Transaction {
  const from = Address.fromString(txParams.from)
  delete txParams.from

  const opts = { common: this._common, freeze: false }
  const tx = Transaction.fromTxData(txParams, opts)

  // override getSenderAddress
  tx.getSenderAddress = () => { return from }

  return tx
}

API

Docs

Generated TypeDoc API Documentation

BigInt Support

Starting with v4 the usage of BN.js for big numbers has been removed from the library and replaced with the usage of the native JS BigInt data type (introduced in ES2020).

Please note that number-related API signatures have changed along with this version update and the minimal build target has been updated to ES2020.

EthereumJS

See our organizational documentation for an introduction to EthereumJS as well as information on current standards and best practices. If you want to join for work or carry out improvements on the libraries, please review our contribution guidelines first.

License

MPL-2.0