refactor: address initial comments

Author: giorgi-kiknavelidze

packages/payment-processor/src/payment/erc20-fee-proxy.ts

@@ -52,7 +52,6 @@ export async function payErc20FeeProxyRequest(
  * @param signerOrProvider the Web3 provider, or signer. Defaults to window.ethereum.
  * @param amount optionally, the amount to pay. Defaults to remaining amount of the request.
  * @param feeAmount optionally, the fee amount to pay. Defaults to the fee amount.
- * @param overrides optionally, override default transaction values, like gas.
  */
 export async function payPrivateErc20FeeProxyRequest(
   request: ClientTypes.IRequestData,

packages/payment-processor/src/payment/prepare-hinkal.ts

@@ -3,8 +3,13 @@ import { Signer } from 'ethers';
 import { Hinkal, exportEthersProvider, preProcessing } from '@hinkal/common';
 
 /**
- * prepares wrapper hinkal object for private transaction
- * @param signer signer object to be passed
+ * Prepares a wrapper Hinkal object for private transactions.
+ * This function initializes the necessary components for private transaction processing
+ * including provider setup, user keys, and Merkle tree initialization.
+ *
+ * @param signer - The ethers.js Signer instance for transaction signing
+ * @returns Promise<Hinkal<unknown>> - A configured Hinkal instance ready for private transactions
+ * @throw If initialization of provider, user keys, or Merkle tree fails
  */
 export const prepareHinkal = async (signer: Signer): Promise<Hinkal<unknown>> => {
   await preProcessing();
@@ -15,6 +20,7 @@ export const prepareHinkal = async (signer: Signer): Promise<Hinkal<unknown>> =>
   await hinkal.initProviderAdapter(undefined, ethersProvider);
   await hinkal.initUserKeys();
 
+  // initialize merkle trees
   await hinkal.resetMerkle();
 
   return hinkal;

packages/payment-processor/src/payment/prepared-transaction.ts

@@ -6,8 +6,12 @@ export interface IPreparedTransaction {
   to: string;
 }
 
+/** Interface for preparing private transactions using Hinkal middleware */
 export interface IPreparedPrivateTransaction {
+  /** Amount to pay in base units (wei or the smallest possible unit of ERC20 token) */
   amountToPay: bigint;
+  /** ERC20 token contract address */
   tokenAddress: string;
+  /** list of operations encoded as HexStrings */
   ops: string[];
 }

packages/usage-examples/src/hinkal/createRequestForHinkal.ts

@@ -1,21 +1,24 @@
 import { ethers } from 'ethers';
 import { RequestNetwork, Types, Utils } from '@requestnetwork/request-client.js';
 import { EthereumPrivateKeySignatureProvider } from '@requestnetwork/epk-signature';
-import { CurrencyTypes } from '@requestnetwork/types';
-
-// Example Data:
-const currencyAddress = '0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85'; // USDC
-const currencyAmount = ethers.utils.parseUnits('0.01', 6).toBigInt();
-const currentNetwork = 'sepolia' as CurrencyTypes.ChainName;
-const currentCurrenyType = Types.RequestLogic.CURRENCY.ERC20;
-const currentGateway = 'https://sepolia.gateway.request.network';
-const payee = '0xA4faFa5523F63EE58aE7b56ad8EB5a344A19F266'; // some random address
-const fee = '0';
-const contentData = {
-  reason: 'Hinkal Test',
-  dueDate: '2025.06.16',
-};
+import {
+  contentData,
+  currencyAddress,
+  currencyAmount,
+  currentCurrenyType,
+  currentGateway,
+  currentNetwork,
+  fee,
+  payee,
+} from './hinkalRequestData';
 
+/**
+ * Creates a payment request with the parameters specified in './hinkalRequestData.ts'
+ * used by testPayErc20FeeProxyRequestHinkal.ts
+ * @param payerWallet the wallet used by the payer
+ * @param privateKey the private of the user creating the request
+ * @returns Newly created request
+ */
 export const createRequestForHinkal = async (
   payerWallet: ethers.Wallet,
   privateKey: string,

packages/usage-examples/src/hinkal/hinkalRequestData.ts

@@ -0,0 +1,15 @@
+import { ethers } from 'ethers';
+import { Types } from '@requestnetwork/request-client.js';
+import { CurrencyTypes } from '@requestnetwork/types';
+
+export const currencyAddress = '0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85'; // USDC
+export const currencyAmount = ethers.utils.parseUnits('0.01', 6).toBigInt();
+export const currentNetwork: CurrencyTypes.ChainName = 'optimism';
+export const currentCurrenyType = Types.RequestLogic.CURRENCY.ERC20;
+export const currentGateway = 'https://sepolia.gateway.request.network';
+export const payee = '0xA4faFa5523F63EE58aE7b56ad8EB5a344A19F266'; // some random address
+export const fee = '0';
+export const contentData = {
+  reason: 'Hinkal Test',
+  dueDate: '2025.06.16',
+};

packages/usage-examples/src/hinkal/testPayErc20FeeProxyRequestHinkal.ts

@@ -7,11 +7,14 @@ config();
 // Usage Example of Private Transactions using Hinkal on Optimism
 // You will need to pass PAYER_PRIVATE_KEY to .env file in usage_examples root (make sure dotenv is installed)
 // run --> yarn start:hinkal
+// IMPORTANT: Ensure your account has sufficient USDC balance before running
+// SECURITY: Handle private keys with extreme caution. Never commit .env file
+// NOTE: Ensure sufficient ETH for gas fees on Optimism network yarn start:hinkal
 
 void (async () => {
-  const RPC_URL = 'https://mainnet.optimism.io';
-  const { PAYER_PRIVATE_KEY } = process.env;
+  const { PAYER_PRIVATE_KEY, OPTIMISM_RPC_URL } = process.env;
   if (!PAYER_PRIVATE_KEY) throw new Error('PRIVATE_KEY_MISSING');
+  const RPC_URL = OPTIMISM_RPC_URL || 'https://mainnet.optimism.io';
 
   // Create Provider and Signer
   const provider = new ethers.providers.JsonRpcProvider(RPC_URL);