Generate Merkle Tree

gistfile1.txt

import keccak256 from "keccak256";
import { MerkleTree } from "merkletreejs";
import fs from "fs";

const leafValues = [];
let tree;
let root;

/**
 *  Creates a new file called 'MerkleTree.txt' that contains
 *  the generated Merkle tree from the 'MerkleLeaves.json' file
 */
export async function generateMerkleTree(data) {
    try {
        console.log(`\nGenerating a Merkle Tree...`);
        tree = new MerkleTree(data, keccak256, {sortPairs: true, sortLeaves: true, sort: true, hashLeaves: true});
        root = tree.getHexRoot();

        // For a short list, you can log it out, but not recommended for large lists
        console.log('\nTree:', tree.toString());
        
        fs.writeFileSync('../example/MerkleTree.txt', tree.toString());
        console.log(`Merkle tree generated.
            \nRoot hash is ${tree.getHexRoot()}
            \nTree Summary:
            \n     Leaf Count: ${tree.getLeafCount()}
            \n     Layer Count: ${tree.getLayerCount()}
            \n     Tree Depth: ${tree.getDepth()}
            \nSaving to MerkleTree.txt
        `);
    } catch (e) {
        console.log(e);
    }
}

/*
 *  Save the root hash to a file 'MerkleRoot.json'
 */
async function saveMerkleRoot() {
    fs.writeFileSync('../example/MerkleRoot.json', JSON.stringify(root));
    console.log(`Saving the Merkle Root '${root}' to 'MerkleRoot.json'`);
}

/*
 *  Main function that is called. It will run the sequence of
 *  of calls to generate the leaves array, the Merkle tree
 *  and the root hash.
 */
export async function generate(data) {
    try {
        for (let i = 0; i < data.length; i ++) {
            let currentHash;
            let currentValue;
            currentValue = data[i];
            currentHash = `0x${keccak256(data[i]).toString('hex')}`;
            /*
            *  Create an object for each gene containing:
            *  gene symbol, keccak256 hash, leaf index
            */
            leafValues.push({ "Leaf": currentValue, "Hash": currentHash})
        }
    } catch (err) {
        console.log(err);
    }

    // Generate a file containing a summary of the Merkle Tree
    fs.writeFileSync("../example/MerkleTreeSummary.json", JSON.stringify(leafValues));

    generateMerkleTree(data)
    .then(saveMerkleRoot());
}