Build Transactions Merkle Tree

buildTransactionsMerkleTree.ts

import {QueryParams, RepositoryFactoryHttp, UInt64} from "nem2-sdk";
import {MerkleTree} from "merkletreejs/index";
import {sha3_256} from "js-sha3";

const  example = async () => {
    const nodeUrl = 'http://api-xym-3-01.ap-northeast-1.nemtech.network:3000';
    const repositoryHttp = new RepositoryFactoryHttp(nodeUrl);
    const blockHttp = repositoryHttp.createBlockRepository();
    // replace with block height
    const height = UInt64.fromUint(1);

    // 1. Obtain HRoot; in Symbol, this is stored in the block header.
    const HRoot = (await blockHttp.getBlockByHeight(height).toPromise()).blockTransactionsHash;
    // 2. Calculate HRoot0 creating a merkle tree with all the transactions within the block in natural order.
    const transactions = await blockHttp.getBlockTransactions(height, new QueryParams(100)).toPromise();
    const leaves = transactions
        .sort((n1,n2) => n1.transactionInfo.index - n2.transactionInfo.index)
        .map(transaction => transaction.transactionInfo!.hash);
    const tree = new MerkleTree(leaves, sha3_256, {
        duplicateOdd: true,
        hashLeaves: false,
        sort: false,
        sortLeaves: false,
        sortPairs: false,
        isBitcoinTree: false});
        const HRoot0 = tree.getRoot().toString('hex');
    // 3. Compare HRoot and HRoot0.
    return HRoot.toUpperCase() === HRoot0.toUpperCase();
}

example().then(result => console.log(result));