Is there a way to batch together spl-token sdk transactions?

Question

I have a program that is creating a mint account, the associated token account, the meta data account. Right now I'm just testing it out without a frontend, but eventually I want to batch them all together into one transaction. The reason why is because I also want to make function callers pay a fee to a certain address. I have the following functions from the @solana/spl-token library, how can I modify them all to be added to the Web3.js Transaction class?

Here's what I have for the two I couldn't figure out:

    const transactionSignature = await token.mintTo(
        connection,
        payer,
        mint,
        destination,
        authority,
        amount
    )

    const tokenAccount = await token.createAssociatedTokenAccount(connection, payer, mint, owner)

Is it good practice to just have separate transactions? In this case, paying the fee would come first. If not, how can I bundle these two and send them together as transactions? I see that the second transaction depends on the mint variable I've never done them separate before so I'm not sure how unconventional it would really be

Answer 1

mintTo and createAssociatedTokenAccount are helper functions that automatically sends the transactions to mint tokens / create an associated token account.

A transaction on Solana can be thought of a request to process one or multiple instructions. Note that instructions in a transaction are processed sequentially, in the order they are added to a transaction.

You can build the instructions individually and then add to a single transaction.

Here is a Solana Playground example that creates a new mint account, creates an associated token account, and mints tokens in a single transaction.

import {
  Connection,
  Keypair,
  SystemProgram,
  Transaction,
  clusterApiUrl,
  sendAndConfirmTransaction,
} from "@solana/web3.js";
import {
  MINT_SIZE,
  TOKEN_PROGRAM_ID,
  createInitializeMint2Instruction,
  getMinimumBalanceForRentExemptMint,
  getAssociatedTokenAddressSync,
  createAssociatedTokenAccountInstruction,
  createMintToInstruction,
} from "@solana/spl-token";

// Playground wallet
const payer = pg.wallet.keypair;

// Connection to devnet cluster
const connection = new Connection(clusterApiUrl("devnet"), "confirmed");

// Generate keypair to use as address of mint account
const mint = new Keypair();
// Authority that can mint new tokens
const mintAuthority = pg.wallet.publicKey;

// Get associated token account address
const associatedTokenAccountAddress = getAssociatedTokenAddressSync(
  mint.publicKey, // mint address
  payer.publicKey // token account owner
);

// Calculate minimum lamports for space required by mint account
const lamports = await getMinimumBalanceForRentExemptMint(connection);

// Instruction to create new account with space for new mint account
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: payer.publicKey,
  newAccountPubkey: mint.publicKey,
  space: MINT_SIZE,
  lamports,
  programId: TOKEN_PROGRAM_ID,
});

// Instruction to initialize mint account
const initializeMintInstruction = createInitializeMint2Instruction(
  mint.publicKey,
  2, // decimals
  mintAuthority, // mint authority
  null // freeze authority
);

// Instruction to create associated token account
const associatedTokenAccountInstruction =
  createAssociatedTokenAccountInstruction(
    payer.publicKey, // payer
    associatedTokenAccountAddress, // token account address
    payer.publicKey, // owner
    mint.publicKey // mint address
  );

// Instruction to mint tokens
const mintToInstruction = createMintToInstruction(
  mint.publicKey, // mint address
  associatedTokenAccountAddress, // destination
  mintAuthority, // mint authority
  100 // amount
);

// Build transaction with instructions to:
// 1. Create and Initialize new Mint Account
// 2. Create Associated Token Account
// 3. Mint tokens to Associated Token Account
const transaction = new Transaction().add(
  createAccountInstruction,
  initializeMintInstruction,
  associatedTokenAccountInstruction,
  mintToInstruction
);

// "mint" keypair has to be included as signer because we are using it's publickey as the address of a new account
const transactionSignature = await sendAndConfirmTransaction(
  connection,
  transaction,
  [payer, mint] // signers
);

console.log(
  "\nTransaction Signature:",
  `https://solana.fm/tx/${transactionSignature}?cluster=devnet-solana`
);