鑄幣關閉權限擴展

Name: 使用Web3.js的Token2022
Availability: InStock

MintCloseAuthority 擴展是一個 Mint 擴展，允許權限關閉並回收來自供應量為 0 的 Mint 帳戶的租金。

此擴展對於清理未使用的鑄幣並回收用於支付帳戶租金豁免的 SOL 非常有用。只有當沒有代幣在流通時，鑄幣才可以被關閉。

初始化鑄幣帳戶

要在 Mint 帳戶上初始化 MintCloseAuthority 擴展，我們需要使用 initializeMintCloseAuthority() 函數。

以下是如何使用鑄幣關閉擴展創建鑄幣的方法：

import { Keypair, SystemProgram, Transaction, sendAndConfirmTransaction } from "@solana/web3.js";
import {
  createInitializeMintInstruction,
  createInitializeMintCloseAuthorityInstruction,
  getMintLen,
  ExtensionType,
  TOKEN_2022_PROGRAM_ID,
} from "@solana/spl-token";

const mint = Keypair.generate();

// Calculate the size needed for a Mint account with Mint Close Authority extension
const mintLen = getMintLen([ExtensionType.MintCloseAuthority]);

// Calculate minimum lamports required for rent exemption
const lamports = await connection.getMinimumBalanceForRentExemption(mintLen);

// Create the account with the correct size and owner
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: keypair.publicKey,
  newAccountPubkey: mint.publicKey,
  space: mintLen,
  lamports,
  programId: TOKEN_2022_PROGRAM_ID,
});

// Initialize the Mint Close Authority extension
const initializeMintCloseAuthority = createInitializeMintCloseAuthorityInstruction(
  mint.publicKey,
  keypair.publicKey,
  TOKEN_2022_PROGRAM_ID,
);

// Initialize the mint itself
const initializeMintInstruction = createInitializeMintInstruction(
  mint.publicKey,
  6,
  keypair.publicKey,
  null,
  TOKEN_2022_PROGRAM_ID,
);

// Combine all instructions in the correct order
const transaction = new Transaction().add(
  createAccountInstruction,
  initializeMintCloseAuthority,
  initializeMintInstruction,
);

const signature = await sendAndConfirmTransaction(connection, transaction, [keypair, mint]);

console.log(
  `Mint created! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`,
);

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關閉鑄幣帳戶

如果 Mint 帳戶的供應量為零，CloseMint Authority 可以使用 closeAccount 指令回收該帳戶的租金，如下所示：

const closeMintInstruction = createCloseAccountInstruction(
  mint.publicKey,
  keypair.publicKey,
  keypair.publicKey,
  [],
  TOKEN_2022_PROGRAM_ID,
);

const transaction = new Transaction().add(closeMintInstruction);

const signature = await sendAndConfirmTransaction(connection, transaction, [keypair], {
  skipPreflight: false,
});

console.log(
  `Mint closed! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`,
);

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