[SDK] Adds serializeTransaction function (#2760)

Co-authored-by: Jonas Daniels <jonas.daniels@outlook.com>

Author: gregfromstl

.changeset/gold-jokes-rule.md

@@ -0,0 +1,5 @@
+---
+"thirdweb": minor
+---
+
+Adds serializeTransaction and updates sign return object to include yParity

packages/thirdweb/src/exports/thirdweb.ts

@@ -113,6 +113,7 @@ export {
 } from "../transaction/actions/simulate.js";
 export { waitForReceipt } from "../transaction/actions/wait-for-tx-receipt.js";
 export { signTransaction } from "../transaction/actions/sign-transaction.js";
+export { serializeTransaction } from "../transaction/serialize-transaction.js";
 
 /**
  * EVENTS

packages/thirdweb/src/exports/transaction.ts

@@ -47,6 +47,10 @@ export {
   signTransaction,
   type SignTransactionOptions,
 } from "../transaction/actions/sign-transaction.js";
+export {
+  serializeTransaction,
+  type SerializeTransactionOptions,
+} from "../transaction/serialize-transaction.js";
 
 //types & utils
 export {

packages/thirdweb/src/transaction/actions/sign-transaction.ts

@@ -1,7 +1,8 @@
-import { type TransactionSerializable, serializeTransaction } from "viem";
+import type { TransactionSerializable } from "viem";
 import type { Hex } from "../../utils/encoding/hex.js";
 import { keccak256 } from "../../utils/hashing/keccak256.js";
 import { sign } from "../../utils/signatures/sign.js";
+import { serializeTransaction } from "../serialize-transaction.js";
 
 export type SignTransactionOptions = {
   transaction: TransactionSerializable;
@@ -34,11 +35,13 @@ export function signTransaction({
     transaction = { ...transaction, sidecars: false };
   }
 
-  const serializedTransaction = serializeTransaction(transaction);
+  const serializedTransaction = serializeTransaction({ transaction });
 
   const signature = sign({
     hash: keccak256(serializedTransaction),
     privateKey: privateKey,
   });
-  return serializeTransaction(transaction, signature);
+  return serializeTransaction({
+    transaction: { ...transaction, ...signature },
+  });
 }