refactor(experimental): optimise signTransaction to only encode the m…

…essage once

packages/transactions/src/signatures.ts

@@ -4,7 +4,7 @@ import { isSignerRole } from '@solana/instructions';
 import { Ed25519Signature, signBytes } from '@solana/keys';
 
 import { ITransactionWithFeePayer } from './fee-payer';
-import { CompiledMessage, compileMessage } from './message';
+import { compileMessage } from './message';
 import { getCompiledMessageEncoder } from './serializers/message';
 
 export interface IFullySignedTransaction extends ITransactionWithSignatures {
@@ -63,8 +63,7 @@ export function isTransactionSignature(
     return true;
 }
 
-async function getCompiledMessageSignature(message: CompiledMessage, secretKey: CryptoKey) {
-    const wireMessageBytes = getCompiledMessageEncoder().encode(message);
+async function getCompiledMessageSignature(wireMessageBytes: Uint8Array, secretKey: CryptoKey) {
     const signature = await signBytes(secretKey, wireMessageBytes);
     return signature;
 }
@@ -91,11 +90,12 @@ export async function signTransaction<TTransaction extends Parameters<typeof com
     const compiledMessage = compileMessage(transaction);
     const nextSignatures: Record<Base58EncodedAddress, Ed25519Signature> =
         'signatures' in transaction ? { ...transaction.signatures } : {};
+    const wireMessageBytes = getCompiledMessageEncoder().encode(compiledMessage);
     const publicKeySignaturePairs = await Promise.all(
         keyPairs.map(keyPair =>
             Promise.all([
                 getAddressFromPublicKey(keyPair.publicKey),
-                getCompiledMessageSignature(compiledMessage, keyPair.privateKey),
+                getCompiledMessageSignature(wireMessageBytes, keyPair.privateKey),
             ])
         )
     );