How to Close Token Accounts

You can close a token account if you don't want to use it anymore. There are two situations:
Wrapped SOL - Closing converts Wrapped SOL to SOL
Other Tokens - You can close it only if token account's balance is 0.
import { getCreateAccountInstruction } from "@solana-program/system";
import {
	findAssociatedTokenPda,
	getCloseAccountInstruction,
	getCreateAssociatedTokenInstructionAsync,
	getInitializeMintInstruction,
	getMintSize,
	TOKEN_2022_PROGRAM_ADDRESS,
} from "@solana-program/token-2022";
import {
	airdropFactory,
	appendTransactionMessageInstructions,
	createSolanaRpc,
	createSolanaRpcSubscriptions,
	createTransactionMessage,
	generateKeyPairSigner,
	getSignatureFromTransaction,
	lamports,
	pipe,
	sendAndConfirmTransactionFactory,
	setTransactionMessageFeePayerSigner,
	setTransactionMessageLifetimeUsingBlockhash,
	signTransactionMessageWithSigners,
} from "@solana/kit";

const rpc = createSolanaRpc("http://127.0.0.1:8899");
const rpcSubscriptions = createSolanaRpcSubscriptions("ws://localhost:8900");

/* constants */
const MINT_AUTHORITY = await generateKeyPairSigner();
const DECIMALS = 9;
const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();

let { authorityATA } = await setup();

const closeTokenAccountIx = getCloseAccountInstruction({
	account: authorityATA,
	destination: MINT_AUTHORITY.address,
	owner: MINT_AUTHORITY,
});

const transactionMessage = pipe(
	createTransactionMessage({ version: 0 }),
	(tx) => setTransactionMessageFeePayerSigner(MINT_AUTHORITY, tx),
	(tx) => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),
	(tx) => appendTransactionMessageInstructions([closeTokenAccountIx], tx)
);

const signedTransaction = await signTransactionMessageWithSigners(
	transactionMessage
);

await sendAndConfirmTransactionFactory({ rpc, rpcSubscriptions })(
	signedTransaction,
	{ commitment: "confirmed" }
);

const txSignature = getSignatureFromTransaction(signedTransaction);
console.log("Transaction Signature:", txSignature);

/*
 * The setup function initializes the mint and associated token accounts,
 *
 */
async function setup() {
	await airdropFactory({ rpc, rpcSubscriptions })({
		recipientAddress: MINT_AUTHORITY.address,
		lamports: lamports(1_000_000_000n), // 1 SOL
		commitment: "confirmed",
	});

	const mint = await generateKeyPairSigner();

	const space = BigInt(getMintSize());

	const rent = await rpc.getMinimumBalanceForRentExemption(space).send();

	// create & initialize mint account
	const createAccountInstruction = getCreateAccountInstruction({
		payer: MINT_AUTHORITY,
		newAccount: mint,
		lamports: rent,
		space,
		programAddress: TOKEN_2022_PROGRAM_ADDRESS,
	});

	const initializeMintInstruction = getInitializeMintInstruction({
		mint: mint.address,
		decimals: DECIMALS,
		mintAuthority: MINT_AUTHORITY.address,
	});

	// create token account
	const [authorityATA] = await findAssociatedTokenPda({
		mint: mint.address,
		owner: MINT_AUTHORITY.address,
		tokenProgram: TOKEN_2022_PROGRAM_ADDRESS,
	});

	const crateAuthorityATAInstruction =
		await getCreateAssociatedTokenInstructionAsync({
			payer: MINT_AUTHORITY,
			mint: mint.address,
			owner: MINT_AUTHORITY.address,
		});

	const instructions = [
		createAccountInstruction,
		initializeMintInstruction,
		crateAuthorityATAInstruction,
	];

	const transactionMessage = pipe(
		createTransactionMessage({ version: 0 }),
		(tx) => setTransactionMessageFeePayerSigner(MINT_AUTHORITY, tx),
		(tx) =>
			setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),
		(tx) => appendTransactionMessageInstructions(instructions, tx)
	);

	const signedTransaction = await signTransactionMessageWithSigners(
		transactionMessage
	);

	await sendAndConfirmTransactionFactory({ rpc, rpcSubscriptions })(
		signedTransaction,
		{ commitment: "confirmed" }
	);

	return {
		authorityATA,
	};
}