This is an implementation of the modified merkle patricia tree as specified in the Ethereum Yellow Paper:
The modified Merkle Patricia tree (trie) provides a persistent data structure to map between arbitrary-length binary data (byte arrays). It is defined in terms of a mutable data structure to map between 256-bit binary fragments and arbitrary-length binary data. The core of the trie, and its sole requirement in terms of the protocol specification is to provide a single 32-byte value that identifies a given set of key-value pairs.
The only backing store supported is LevelDB through the levelup module.
npm install merkle-patricia-tree
There are 3 variants of the tree implemented in this library, namely: BaseTrie, CheckpointTrie and SecureTrie. CheckpointTrie adds checkpointing functionality to the BaseTrie with the methods checkpoint, commit and revert. SecureTrie extends CheckpointTrie and is the most suitable variant for Ethereum applications. It stores values under the keccak256 hash of their keys.
import level from 'level'
import { BaseTrie as Trie } from 'merkle-patricia-tree'
const db = level('./testdb')
const trie = new Trie(db)
async function test() {
await trie.put(Buffer.from('test'), Buffer.from('one'))
const value = await trie.get(Buffer.from('test'))
console.log(value.toString()) // 'one'
}
test()const trie = new Trie()
async function test() {
await trie.put(Buffer.from('test'), Buffer.from('one'))
const proof = await Trie.createProof(trie, Buffer.from('test'))
const value = await Trie.verifyProof(trie.root, Buffer.from('test'), proof)
console.log(value.toString()) // 'one'
}
test()import level from 'level'
import { SecureTrie as Trie } from 'merkle-patricia-tree'
const db = level('YOUR_PATH_TO_THE_GETH_CHAIN_DB')
// Set stateRoot to block #222
const stateRoot = '0xd7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544'
// Initialize trie
const trie = new Trie(db, stateRoot)
trie
.createReadStream()
.on('data', console.log)
.on('end', () => {
console.log('End.')
})import level from 'level'
import rlp from 'rlp'
import { BN, bufferToHex } from 'ethereumjs-util'
import Account from 'ethereumjs-account'
import { SecureTrie as Trie } from 'merkle-patricia-tree'
const stateRoot = 'STATE_ROOT_OF_A_BLOCK'
const db = level('YOUR_PATH_TO_THE_GETH_CHAINDATA_FOLDER')
const trie = new Trie(db, stateRoot)
const address = 'AN_ETHEREUM_ACCOUNT_ADDRESS'
async function test() {
const data = await trie.get(address)
const acc = new Account(data)
console.log('-------State-------')
console.log(`nonce: ${new BN(acc.nonce)}`)
console.log(`balance in wei: ${new BN(acc.balance)}`)
console.log(`storageRoot: ${bufferToHex(acc.stateRoot)}`)
console.log(`codeHash: ${bufferToHex(acc.codeHash)}`)
let storageTrie = trie.copy()
storageTrie.root = acc.stateRoot
console.log('------Storage------')
const stream = storageTrie.createReadStream()
stream
.on('data', (data) => {
console.log(`key: ${bufferToHex(data.key)}`)
console.log(`Value: ${bufferToHex(rlp.decode(data.value))}`)
})
.on('end', () => {
console.log('Finished reading storage.')
})
}
test()Additional examples with detailed explanations are available here.
npm test
There are two simple benchmarks in the benchmarks folder:
random.tsruns randomPUToperations on the tree.checkpointing.tsruns checkpoints and commits betweenPUToperations.
A third benchmark using mainnet data to simulate real load is also under consideration.
Benchmarks can be run with:
npm run benchmarksTo run a profiler on the random.ts benchmark and generate a flamegraph with 0x you can use:
npm run profiling0x processes the stacks and generates a profile folder (<pid>.0x) containing flamegraph.html.
- Wiki
- Blog posts
- Ethereum's Merkle Patricia Trees - An Interactive JavaScript Tutorial
- Merkling in Ethereum
- Understanding the Ethereum Trie. Worth a read, but the Python libraries are outdated.
- Videos
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 do improvements on the libraries have a look at our contribution guidelines.
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