Libraries:

✔️ IncrementalBinaryTree (Poseidon)
✔️ IncrementalQuinTree (Poseidon)

The methods of each library are always the same (i.e insert, update, remove, verify).

🛠 Install

npm or yarn

Install the @zk-kit/incremental-merkle-tree.sol package with npm:

npm i @zk-kit/incremental-merkle-tree.sol --save

or yarn:

yarn add @zk-kit/incremental-merkle-tree.sol

📜 Usage

Importing and using the library

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@zk-kit/incremental-merkle-tree.sol/IncrementalBinaryTree.sol";

contract Example {
    using IncrementalBinaryTree for IncrementalTreeData;

    event TreeCreated(bytes32 id, uint256 depth);
    event LeafInserted(bytes32 indexed treeId, uint256 leaf, uint256 root);
    event LeafUpdated(bytes32 indexed treeId, uint256 leaf, uint256 root);
    event LeafRemoved(bytes32 indexed treeId, uint256 leaf, uint256 root);

    mapping(bytes32 => IncrementalTreeData) public trees;

    function createTree(bytes32 _id, uint256 _depth) external {
        require(trees[_id].depth == 0, "Example: tree already exists");

        trees[_id].init(_depth, 0);

        emit TreeCreated(_id, _depth);
    }

    function insertLeaf(bytes32 _treeId, uint256 _leaf) external {
        require(trees[_treeId].depth != 0, "Example: tree does not exist");

        trees[_treeId].insert(_leaf);

        emit LeafInserted(_treeId, _leaf, trees[_treeId].root);
    }

    function updateLeaf(
        bytes32 _treeId,
        uint256 _leaf,
        uint256 _newLeaf,
        uint256[] calldata _proofSiblings,
        uint8[] calldata _proofPathIndices
    ) external {
        require(trees[_treeId].depth != 0, "Example: tree does not exist");

        trees[_treeId].update(_leaf, _newLeaf, _proofSiblings, _proofPathIndices);

        emit LeafUpdated(_treeId, _newLeaf, trees[_treeId].root);
    }

    function removeLeaf(
        bytes32 _treeId,
        uint256 _leaf,
        uint256[] calldata _proofSiblings,
        uint8[] calldata _proofPathIndices
    ) external {
        require(trees[_treeId].depth != 0, "Example: tree does not exist");

        trees[_treeId].remove(_leaf, _proofSiblings, _proofPathIndices);

        emit LeafRemoved(_treeId, _leaf, trees[_treeId].root);
    }
}

Creating an Hardhat task to deploy the contract

import { poseidon_gencontract as poseidonContract } from "circomlibjs"
import { Contract } from "ethers"
import { task, types } from "hardhat/config"

task("deploy:example", "Deploy an Example contract")
    .addOptionalParam<boolean>("logs", "Print the logs", true, types.boolean)
    .setAction(async ({ logs }, { ethers }): Promise<Contract> => {
        const poseidonT3ABI = poseidonContract.generateABI(2)
        const poseidonT3Bytecode = poseidonContract.createCode(2)

        const [signer] = await ethers.getSigners()

        const PoseidonLibT3Factory = new ethers.ContractFactory(poseidonT3ABI, poseidonT3Bytecode, signer)
        const poseidonT3Lib = await PoseidonLibT3Factory.deploy()

        await poseidonT3Lib.deployed()

        logs && console.log(`PoseidonT3 library has been deployed to: ${poseidonT3Lib.address}`)

        const IncrementalBinaryTreeLibFactory = await ethers.getContractFactory("IncrementalBinaryTree", {
            libraries: {
                PoseidonT3: poseidonT3Lib.address
            }
        })
        const incrementalBinaryTreeLib = await IncrementalBinaryTreeLibFactory.deploy()

        await incrementalBinaryTreeLib.deployed()

        logs && console.log(`IncrementalBinaryTree library has been deployed to: ${incrementalBinaryTreeLib.address}`)

        const ContractFactory = await ethers.getContractFactory("Example", {
            libraries: {
                IncrementalBinaryTree: incrementalBinaryTreeLib.address
            }
        })

        const contract = await ContractFactory.deploy()

        await contract.deployed()

        logs && console.log(`Example contract has been deployed to: ${contract.address}`)

        return contract
    })

Contacts

Developers

• e-mail : [email protected]
• github : @cedoor
• website : https://cedoor.dev