get status of a payment via the reference public key (solana pay)

solana-pay.test.ts

import { test } from "vitest";
import {
  Connection,
  Keypair,
  LAMPORTS_PER_SOL,
  PublicKey,
  sendAndConfirmTransaction,
  SystemProgram,
  Transaction,
} from "@solana/web3.js";
import { validateTransfer } from "@solana/pay";
import { BigNumber } from "bignumber.js";
import base58 from "bs58";
import dotenv from "dotenv";

dotenv.config();

test("verify transaction", async () => {
  // hardcoded solana values for testing
  const connection = new Connection("http://127.0.0.1:8899");
  const reference = Keypair.generate();
  const alice = Keypair.fromSecretKey(
    base58.decode(process.env.FAUCET_SECRET_KEY!)
  );
  const bob = new PublicKey("2S9jKJEGKoVxR3xkEfFyGVrLwJj1H8xYjqtSP5LAX97x");

  // just verifying stuff
  console.log(`Alice - ${alice.publicKey.toString()}`);
  console.log(`Bob - ${bob.toString()}`);

  // airdrop sol
  const airdropSignature = await connection.requestAirdrop(
    alice.publicKey,
    1 * LAMPORTS_PER_SOL
  );
  console.log(
    `Airdropped 1 SOL to ${alice.publicKey.toString()} - ${airdropSignature}`
  );

  // creating a listener which finds a transaction having the `reference` public key
  connection.onLogs(reference.publicKey, async (logs, _context) => {
    console.log(`connection.onLogs fn - ${logs.signature}`);

    try {
      // validating the transfer
      await validateTransfer(connection, logs.signature, {
        recipient: bob,
        amount: new BigNumber(0.0005),
        reference: reference.publicKey,
      });
      console.log("Transfer validated");
    } catch (err) {
      console.log("Invalid transfer");
    }
  });

  // just a simple SOL transfer instruction
  const feeTransferInstruction = SystemProgram.transfer({
    fromPubkey: alice.publicKey,
    toPubkey: bob,
    lamports: 0.0005 * LAMPORTS_PER_SOL,
  });
  // adding the `reference` public key into the instruction's keys
  feeTransferInstruction.keys.push({
    pubkey: reference.publicKey,
    isSigner: false,
    isWritable: false,
  });

  const transaction = new Transaction();
  transaction.add(feeTransferInstruction);

  const { blockhash } = await connection.getLatestBlockhash();
  transaction.recentBlockhash = blockhash;
  transaction.feePayer = alice.publicKey;

  // signing a sending the transaction
  const signature = await sendAndConfirmTransaction(connection, transaction, [
    alice,
  ]);

  // for verifying whether the signature from .onLogs fn is correct or not
  console.log(`Signature - ${signature}`);

  // added this 'cause sometimes the .onLogs fn doesn't catch the signature on the spot, so wait for 500ms before the test gets exited
  const sleep = (ms: number) => {
    return new Promise((resolve) => {
      setTimeout(resolve, ms);
    });
  };

  await sleep(500);
});