refactor: add constant for max Transaction size

web3.js/src/loader.js

@@ -23,7 +23,6 @@ export class Loader {
    */
   programId: PublicKey;
 
-
   /**
    * Amount of program data placed in each load Transaction
    */

web3.js/src/transaction.js

@@ -19,6 +19,11 @@ export type TransactionSignature = string;
  */
 export type TransactionId = string;
 
+/**
+ * Maximum over-the-wire size of a Transaction
+ */
+export const PACKET_DATA_SIZE = 512;
+
 /**
  * List of TransactionInstruction object fields that may be initialized at construction
  *
@@ -290,8 +295,8 @@ export class Transaction {
     });
     signData.copy(wireTransaction, 8 + signatures.length * 64);
     invariant(
-      wireTransaction.length < 512,
-      `${wireTransaction.length}, ${signatures.length}`,
+      wireTransaction.length <= PACKET_DATA_SIZE,
+      `Transaction too large: ${wireTransaction.length} > ${PACKET_DATA_SIZE}`,
     );
     return wireTransaction;
   }