Solana Create Nonce Account

AccHelper.js

import {
  Keypair,
  NONCE_ACCOUNT_LENGTH,
  SystemProgram,
  TransactionMessage,
  VersionedTransaction
} from "@solana/web3.js";

class AccHelper {
  /**
   * 
   * @description Create a new NONCE Account
   * @param {Connection} connection - The connection object to custom RPC
   * @param {Keypair} authority - The authority keypair
   * @param {Keypair} feePayer - The fee payer keypair (usually the wallet signer & 1st signer in the transaction**)
   * @returns {Promise<object>} - The account object
   * @example
   * const account = await Account.createAccount(connection, authority, feePayer);
   * console.log(account);
   */
  static async createNonceAccount({ connection, authority, dapp }) {

    const nAcc = Keypair.generate();
    // Instructions 
    const instructions = [
      SystemProgram.createAccount({
        fromPubkey: authority.publicKey,
        newAccountPubkey: nAcc.publicKey,
        lamports: await connection.getMinimumBalanceForRentExemption(
          NONCE_ACCOUNT_LENGTH
        ),
        space: NONCE_ACCOUNT_LENGTH,
        programId: SystemProgram.programId,
      }),
      SystemProgram.nonceInitialize({
        noncePubkey: nAcc.publicKey,
        authorizedPubkey: dapp, // nonce account authority (for advance and close)
      })
    ];
    // Message 
    const messageV0 = new TransactionMessage({
      payerKey: authority.publicKey,
      recentBlockhash: (await connection.getRecentBlockhash()).blockhash,
      instructions,
    }).compileToV0Message();
    // Signing 
    const transactionV0 = new VersionedTransaction(messageV0);
    transactionV0.sign([nAcc]);
    console.log("TransactionV0 signed by NEW NonceAccount: ", transactionV0);
    
    const stx = await authority.signTransaction(transactionV0);
    console.log("Signature by Wallet: ", stx);
    // TODO. Is this correct? 
    transactionV0.signatures[0] = stx.signatures[0];

    console.log("TransactionV0 signed by Wallet: ", transactionV0);
    // TODO move elsewhere
    const serialized = transactionV0.serialize();
    localStorage.setItem("serializedTxnSigned", serialized);
    const txId = await connection.sendRawTransaction(serialized);
    console.log("Transaction ID: ", txId);

    return { txId, nAcc };
  }
}

export default AccHelper;