Update getSignature.ts

example/utils/getSignature.ts

@@ -1,17 +1,32 @@
 import bs58 from "bs58";
 import { Transaction, VersionedTransaction } from "@solana/web3.js";
 
+/**
+ * @notice Extracts the primary signature (which acts as the transaction ID) from a Solana transaction object
+ * and encodes it into the Base58 string format.
+ * @param transaction The Solana Transaction (legacy) or VersionedTransaction object.
+ * @returns The Base58-encoded transaction signature string.
+ * @throws Error if the transaction does not contain a signature (meaning it wasn't signed by the fee payer).
+ */
 export function getSignature(
   transaction: Transaction | VersionedTransaction
 ): string {
-  const signature =
-    "signature" in transaction
+  // Use a type guard to correctly access the signature based on the transaction type.
+  // For VersionedTransaction, the first signature in the array is the fee payer's signature (the Tx ID).
+  // For the legacy Transaction type, the signature field is used.
+  const rawSignature: Buffer | Uint8Array | null | undefined =
+    'signature' in transaction 
       ? transaction.signature
       : transaction.signatures[0];
-  if (!signature) {
+
+  // The signature must be present for a transaction to have an ID.
+  if (!rawSignature) {
     throw new Error(
-      "Missing transaction signature, the transaction was not signed by the fee payer"
+      "Missing transaction signature; the transaction was not signed by the fee payer."
     );
   }
-  return bs58.encode(signature);
+
+  // Ensure the signature is encoded correctly from its raw byte format.
+  // We use the 'rawSignature' variable directly for bs58.encode.
+  return bs58.encode(rawSignature);
 }