Merkle tree

Provides implementation for building and managing Merkle tree structure.

Usage

Install package with:

• npm install @laborx/merkletree

or

• yarn add @laborx/merkletree

Main classes

There are two main classes:

• MerkleTree
• AirdropMerkleProofBuilder

MerkleTree class provides functionality to initialize, build, construct merkle proof for provided element and verify passed proof.

AirdropMerkleProofBuilder class provided wrapper around MerkleTree and allowes to speak on a business language rather than low-level instructions. This class uses AirdropNode interface to set up bounds around entity that is supposed to be used throughout class's lifecycle. It will be helpful to coordinate with @laborx/airdrop-contracts smart contracts.

Use cases

MerkleTree class

Creation of MerkleTree

import { MerkleTree, HashFunction } from "@laborx/merkletree";

// ...

const leaves: Buffer[];
const hashAlgorithm: HashAlgorithm; 
const merkleTree = new MerkleTree(leaves, hashAlgorithm)

Then merkle tree is ready to go.

Generate proof for one of your leaf

const leaf: Buffer;
const merkleProof: MerkleProofItem[] = merkleTree.getProof(leaf);

Verify provided proof for validity:

const merkleRoot: Buffer = merkleTree.getRoot();
const leaf: Buffer;
const merkleProof: MerkleProofItem[];

merkleTree.verify(proof, leaf, merkleRoot);

AirdropMerkleProofBuilder class

This class allows easiest acceess and communication with MerkleTree class through lenses of airdrop functionality.

Creation of AirdropMerkleProofBuilder

import { AirdropMerkleProofBuilder, AirdropNode, AirdropProof, makeTreeLeafString } from "@laborx/merkletree";

const elements: AirdropNode[];
const airdropProofBuilder = new AirdropMerkleProofBuilder(elements);

Get a merkle proof

const element: AirdropNode;

const proof: AirdropProof[] = airdropProofBuilder.getProofForNode(element);

Verify your node of merkle tree entrance

const proof: AirdropProof[];
const element: AirdropNode;

const isValidElement: boolean = airdropProofBuilder.verifyProofForNode(proof, element);

Compile updated version of elements

When existed elements are updated and initial merkle tree have to be updated too just do

const updatedElement: AirdropNode[];

airdropProofBuilder.compileNewMerkleTree(updatedElement);