Blockchain Development Programming Tutorials, Guides & Best Practices

We'll now write a function to track a specific Solana address and log new trades:

async function trackAddress(address) {
  try {
    const publicKey = new solanaWeb3.PublicKey(address);

    console.log(`Tracking address: ${publicKey.toBase58()}`);

    let lastSignature = '';

    // Fetch initial transactions
    const signatures = await connection.getSignaturesForAddress(publicKey, { limit: 1 });
    if (signatures.length > 0) {
      lastSignature = signatures[0].signature;
    }

    // Monitor for new transactions
    setInterval(async () => {
      const signatures = await connection.getSignaturesForAddress(publicKey, {
        limit: 10,
      });

      for (const signatureInfo of signatures) {
        if (signatureInfo.signature !== lastSignature) {
          const transaction = await connection.getConfirmedTransaction(signatureInfo.signature);

          if (transaction) {
            const { meta, transaction: tx } = transaction;

            const instructions = tx.message.instructions;
            const postBalances = meta.postBalances;
            const preBalances = meta.preBalances;

            // Check if the transaction involves token transfers
            instructions.forEach((instruction, index) => {
              const programId = instruction.programId.toBase58();

              // Solana's SPL Token Program ID
              if (programId === solanaWeb3.TOKEN_PROGRAM_ID.toBase58()) {
                const data = Buffer.from(instruction.data);
                const command = data.readUInt8(0);

                // 3 represents the Token Transfer instruction
                if (command === 3) {
                  const amount = data.readUInt64LE(1);
                  const fromAccount = instruction.keys[0].pubkey.toBase58();
                  const toAccount = instruction.keys[1].pubkey.toBase58();

                  const balanceChange = (preBalances[index] - postBalances[index]) / solanaWeb3.LAMPORTS_PER_SOL;

                  console.log(`New Trade Detected!`);
                  console.log(`- Signature: ${signatureInfo.signature}`);
                  console.log(`- From: ${fromAccount}`);
                  console.log(`- To: ${toAccount}`);
                  console.log(`- Amount: ${balanceChange} SOL`);
                }
              }
            });
          }

          lastSignature = signatureInfo.signature;
        }
      }
    }, 10000); // Check every 10 seconds
  } catch (error) {
    console.error('Error tracking address:', error);
  }
}

// Replace with the Solana address you want to track
const addressToTrack = 'YourSolanaAddressHere';
trackAddress(addressToTrack);