feat: added createTransaction (#6)

* feat: added createTransaction

* chore: changeset

.changeset/wise-wasps-lick.md

@@ -0,0 +1,5 @@
+---
+"gill": patch
+---
+
+added the `createTransaction` function

packages/gill/src/core/index.ts

@@ -1,3 +1,4 @@
 export * from "./const";
 export * from "./rpc";
 export * from "./explorer";
+export * from "./transactions";

packages/gill/src/core/transactions.ts

@@ -0,0 +1,31 @@
+import {
+  pipe,
+  isTransactionSigner,
+  createTransactionMessage,
+  setTransactionMessageFeePayer,
+  setTransactionMessageFeePayerSigner,
+  appendTransactionMessageInstructions,
+  setTransactionMessageLifetimeUsingBlockhash,
+} from "@solana/web3.js";
+import type { CreateTransactionInput } from "../types/transactions";
+
+/**
+ * Simple interface for creating a Solana transaction
+ */
+export function createTransaction({
+  version,
+  feePayer,
+  instructions,
+  latestBlockhash,
+}: CreateTransactionInput) {
+  return pipe(
+    createTransactionMessage({ version }),
+    (tx) => {
+      if ("address" in feePayer && isTransactionSigner(feePayer)) {
+        return setTransactionMessageFeePayerSigner(feePayer, tx);
+      } else return setTransactionMessageFeePayer(feePayer, tx);
+    },
+    (tx) => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),
+    (tx) => appendTransactionMessageInstructions(instructions, tx),
+  );
+}

packages/gill/src/types/transactions.ts

@@ -0,0 +1,28 @@
+import type {
+  Address,
+  Blockhash,
+  IInstruction,
+  TransactionSigner,
+  TransactionVersion,
+} from "@solana/web3.js";
+
+export type CreateTransactionInput = {
+  /**
+   * Transaction version
+   * - `legacy` is commonly used
+   * - `0` is needed for use with Address Lookup Tables
+   * */
+  version: TransactionVersion;
+  /** List of instructions for this transaction */
+  instructions: IInstruction[];
+  /** Address or Signer that will pay transaction fees */
+  feePayer: Address | TransactionSigner;
+  /**
+   * Latest blockhash (aka transaction lifetime) for this transaction to
+   * accepted for execution on the Solana network
+   * */
+  latestBlockhash: Readonly<{
+    blockhash: Blockhash;
+    lastValidBlockHeight: bigint;
+  }>;
+};