Group, Group Pointer, Member, Member Pointer

Summary

'token groups' are commonly used to implement NFT collections.
The group pointer extension sets a group account on the token mint, to hold token group information.
The group extension allows us to save group data within the mint itself.
The member pointer extension sets an individual member account on the token mint, to hold information about the token's membership within a group.
The member extension allows us to save member data within the mint itself.

SPL tokens are valuable alone but can be combined for extra functionality. We can do this in the Token Extensions Program by combining the group, group pointer, member, and member pointer extensions. The most common use case for these extensions is to create a collection of NFTs.

To create a collection of NFTs we need two parts: the "collection" NFT and all of the NFTs within the collection. We can do this entirely using token extensions. The "collection" NFT can be a single mint combining the metadata, metadata pointer, group, and group pointer extensions. And then each individual NFT within the collection can be an array of mints combining the metadata, metadata pointer, member, and member pointer extensions.

Although NFT collections are a common use-case, groups and members can be applied to any token type.

A quick note on group pointer vs group. The group pointer extension saves the address of any onchain account that follows to the Token-Group Interface. While the group extension saves the Token-Group Interface data directly within the mint account. Generally, these are used together where the group pointer points to the mint itself. The same is true for member pointer vs member, but with the member data.

NOTE: A group can have many members, but a member can only belong to one group.

Group and Group Pointer

The group and group pointer extensions define a token group. The onchain data is as follows:

update_authority: The authority that can sign to update the group.
mint: The mint of the group token.
size: The current number of group members.
max_size: The maximum number of group members.

type OptionalNonZeroPubkey = Pubkey; // if all zeroes, interpreted as `None`
type PodU32 = [u8; 4];
type Pubkey = [u8; 32];
 
/// Type discriminant: [214, 15, 63, 132, 49, 119, 209, 40]
/// First 8 bytes of `hash("spl_token_group_interface:group")`
pub struct TokenGroup {
    /// The authority that can sign to update the group
    pub update_authority: OptionalNonZeroPubkey,
    /// The associated mint, used to counter spoofing to be sure that group
    /// belongs to a particular mint
    pub mint: Pubkey,
    /// The current number of group members
    pub size: PodU32,
    /// The maximum number of group members
    pub max_size: PodU32,
}

Creating a mint with group and group pointer

Creating a mint with the group and group pointer involves four instructions:

SystemProgram.createAccount
createInitializeGroupPointerInstruction
createInitializeMintInstruction
createInitializeGroupInstruction

The first instruction SystemProgram.createAccount allocates space on the blockchain for the mint account. However like all Token Extensions Program mints, we need to calculate the size and cost of the mint. This can be accomplished by using getMintLen and getMinimumBalanceForRentExemption. In this case, we'll call getMintLen with only the ExtensionType.GroupPointer. Then we add TOKEN_GROUP_SIZE to the mint length to account for the group data.

To get the mint length and create account instruction, do the following:

// get mint length
const extensions = [ExtensionType.GroupPointer];
const mintLength = getMintLen(extensions) + TOKEN_GROUP_SIZE;
 
const mintLamports =
  await connection.getMinimumBalanceForRentExemption(mintLength);
 
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: payer.publicKey,
  newAccountPubkey: mintKeypair.publicKey,
  space: mintLength,
  lamports: mintLamports,
  programId: TOKEN_2022_PROGRAM_ID,
});

The second instruction createInitializeGroupPointerInstruction initializes the group pointer. It takes the mint, optional authority that can set the group address, address that holds the group and the owning program as it's arguments.

const initializeGroupPointerInstruction =
  createInitializeGroupPointerInstruction(
    mintKeypair.publicKey,
    payer.publicKey,
    mintKeypair.publicKey,
    TOKEN_2022_PROGRAM_ID,
  );

The third instruction createInitializeMintInstruction initializes the mint.

const initializeMintInstruction = createInitializeMintInstruction(
  mintKeypair.publicKey,
  decimals,
  payer.publicKey,
  payer.publicKey,
  TOKEN_2022_PROGRAM_ID,
);

The fourth instruction createInitializeGroupInstruction actually initializes the group and stores the configuration on the group account.

const initializeGroupInstruction = createInitializeGroupInstruction({
  group: mintKeypair.publicKey,
  maxSize: maxMembers,
  mint: mintKeypair.publicKey,
  mintAuthority: payer.publicKey,
  programId: TOKEN_2022_PROGRAM_ID,
  updateAuthority: payer.publicKey,
});

Finally, we add the instructions to the transaction and submit it to the Solana network.

const mintTransaction = new Transaction().add(
  createAccountInstruction,
  initializeGroupPointerInstruction,
  initializeMintInstruction,
  initializeGroupInstruction,
);
 
const signature = await sendAndConfirmTransaction(
  connection,
  mintTransaction,
  [payer, mintKeypair],
  { commitment: "finalized" },
);

Update group authority

To update the authority of a group, we just need the tokenGroupUpdateGroupAuthority function.

import { tokenGroupUpdateGroupAuthority } from "@solana/spl-token";
 
const signature = await tokenGroupUpdateGroupAuthority(
  connection, //connection - Connection to use
  payer, // payer - Payer for the transaction fees
  mint.publicKey, // mint - Group mint
  oldAuthority, // account - Public key of the old update authority
  newAuthority, // account - Public key of the new update authority
  undefined, // multiSigners - Signing accounts if `authority` is a multisig
  { commitment: "finalized" }, // confirmOptions - Options for confirming thr transaction
  TOKEN_2022_PROGRAM_ID, // programId - SPL Token program account
);

Update max size of a group

To update the max size of a group we just need the tokenGroupUpdateGroupMaxSize function.

import { tokenGroupUpdateGroupMaxSize } from "@solana/spl-token";
 
const signature = tokenGroupUpdateGroupMaxSize(
  connection, //connection - Connection to use
  payer, // payer - Payer for the transaction fees
  mint.publicKey, // mint - Group mint
  updateAuthority, // account - Update authority of the group
  4, // maxSize - new max size of the group
  undefined, // multiSigners — Signing accounts if `authority` is a multisig
  { commitment: "finalized" }, // confirmOptions - Options for confirming thr transaction
  TOKEN_2022_PROGRAM_ID, // programId - SPL Token program account
);

Member and Member Pointer

The member and member pointer extensions define a token member. The onchain data is as follows:

mint: The mint of the member token.
group: The address of the group account.
member_number: The member number (index within the group).

/// Type discriminant: [254, 50, 168, 134, 88, 126, 100, 186]
/// First 8 bytes of `hash("spl_token_group_interface:member")`
pub struct TokenGroupMember {
    /// The associated mint, used to counter spoofing to be sure that member
    /// belongs to a particular mint
    pub mint: Pubkey,
    /// The pubkey of the `TokenGroup`
    pub group: Pubkey,
    /// The member number
    pub member_number: PodU32,
}

Creating a mint with member pointer

Creating a mint with the member pointer and member extensions involves four instructions:

SystemProgram.createAccount
createInitializeGroupMemberPointerInstruction
createInitializeMintInstruction
createInitializeMemberInstruction

The first instruction SystemProgram.createAccount allocates space on the blockchain for the mint account. However, like all Token Extensions Program mints, we need to calculate the size and cost of the mint. This can be accomplished by using getMintLen and getMinimumBalanceForRentExemption. In this case, we'll call getMintLen with the ExtensionType.GroupMemberPointer. Then we have to add TOKEN_GROUP_MEMBER_SIZE to the mint length to account for the member data.

To get the mint length and create account instruction, do the following:

// get mint length
const extensions = [ExtensionType.GroupMemberPointer];
const mintLength = getMintLen(extensions) + TOKEN_GROUP_MEMBER_SIZE;
 
const mintLamports =
  await connection.getMinimumBalanceForRentExemption(mintLength);
 
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: payer.publicKey,
  newAccountPubkey: mintKeypair.publicKey,
  space: mintLength,
  lamports: mintLamports,
  programId: TOKEN_2022_PROGRAM_ID,
});

The second instruction createInitializeGroupMemberPointerInstruction initializes the group member pointer. It takes the mint, optional authority that can set the group address, address that holds the group, and the owning program as its arguments.

const initializeGroupMemberPointerInstruction =
  createInitializeGroupMemberPointerInstruction(
    mintKeypair.publicKey,
    payer.publicKey,
    mintKeypair.publicKey,
    TOKEN_2022_PROGRAM_ID,
  );

The third instruction createInitializeMintInstruction initializes the mint.

const initializeMintInstruction = createInitializeMintInstruction(
  mintKeypair.publicKey,
  decimals,
  payer.publicKey,
  payer.publicKey,
  TOKEN_2022_PROGRAM_ID,
);

The fourth instruction createInitializeMemberInstruction actually initializes the member and stores the configuration on the member account. This function takes the group address as an argument and associates the member with that group.

const initializeMemberInstruction = createInitializeMemberInstruction({
  group: groupAddress,
  groupUpdateAuthority: payer.publicKey,
  member: mintKeypair.publicKey,
  memberMint: mintKeypair.publicKey,
  memberMintAuthority: payer.publicKey,
  programId: TOKEN_2022_PROGRAM_ID,
});

Finally, we add the instructions to the transaction and submit it to the Solana network.

const mintTransaction = new Transaction().add(
  createAccountInstruction,
  initializeGroupMemberPointerInstruction,
  initializeMintInstruction,
  initializeMemberInstruction,
);
 
const signature = await sendAndConfirmTransaction(
  connection,
  mintTransaction,
  [payer, mintKeypair],
  { commitment: "finalized" },
);

Fetch group and member data

Get group pointer state

To retrieve the state of the group pointer for a mint, we need to fetch the account using getMint and then parse this data using the getGroupPointerState function. This returns us the GroupPointer struct.

/** GroupPointer as stored by the program */
export interface GroupPointer {
  /** Optional authority that can set the group address */
  authority: PublicKey | null;
  /** Optional account address that holds the group */
  groupAddress: PublicKey | null;
}

To get the GroupPointer data, call the following:

const groupMint = await getMint(
  connection,
  mint,
  "confirmed",
  TOKEN_2022_PROGRAM_ID,
);
 
const groupPointerData: GroupPointer = getGroupPointerState(groupMint);

Get group state

To retrieve the group state for a mint, we need to fetch the account using getMint and then parse this data using the getTokenGroupState function. This returns the TokenGroup struct.

export interface TokenGroup {
  /** The authority that can sign to update the group */
  updateAuthority?: PublicKey;
  /** The associated mint, used to counter spoofing to be sure that group belongs to a particular mint */
  mint: PublicKey;
  /** The current number of group members */
  size: number;
  /** The maximum number of group members */
  maxSize: number;
}

To get the TokenGroup data, call the following:

const groupMint = await getMint(
  connection,
  mint,
  "confirmed",
  TOKEN_2022_PROGRAM_ID,
);
 
const groupData: TokenGroup = getTokenGroupState(groupMint);

Get group member pointer state

To retrieve the member pointer state for a mint, we fetch the mint with getMint and then parse with getGroupMemberPointerState. This returns us the GroupMemberPointer struct.

/** GroupMemberPointer as stored by the program */
export interface GroupMemberPointer {
  /** Optional authority that can set the member address */
  authority: PublicKey | null;
  /** Optional account address that holds the member */
  memberAddress: PublicKey | null;
}

To get the GroupMemberPointer data, call the following:

const memberMint = await getMint(
  connection,
  mint,
  "confirmed",
  TOKEN_2022_PROGRAM_ID,
);
 
const memberPointerData = getGroupMemberPointerState(memberMint);

Get group member state

To retrieve a mint's member state, we fetch the mint with getMint and then parse with getTokenGroupMemberState. This returns the TokenGroupMember struct.

export interface TokenGroupMember {
  /** The associated mint, used to counter spoofing to be sure that member belongs to a particular mint */
  mint: PublicKey;
  /** The pubkey of the `TokenGroup` */
  group: PublicKey;
  /** The member number */
  memberNumber: number;
}

To get the TokenGroupMember data, call the following:

const memberMint = await getMint(
  connection,
  mint,
  "confirmed",
  TOKEN_2022_PROGRAM_ID,
);
const memberData = getTokenGroupMemberState(memberMint);

Lab

In this lab we'll create a Cool Cats NFT collection using the group, group pointer, member and member pointer extensions in conjunction with the metadata and metadata pointer extensions.

The Cool Cats NFT collection will have a group NFT with three member NFTs within it.

1. Getting started

To get started, clone this repository's starter branch.

git clone https://github.com/Unboxed-Software/solana-lab-group-member.git
cd solana-lab-group-member
git checkout starter
npm install

The starter code comes with:

index.ts: creates a connection object and calls initializeKeypair. This is where we will write our script.
assets: folder which contains the image for our NFT collection.
helper.ts: helper functions for uploading metadata.

2. Run validator node

For the sake of this guide, we'll be running our own validator node.

In a separate terminal, run the following command: solana-test-validator. This will run the node and also log out some keys and values. The value we need to retrieve and use in our connection is the JSON RPC URL, which in this case is http://127.0.0.1:8899. We then use that in the connection to specify to use the local RPC URL.

const connection = new Connection("http://127.0.0.1:8899", "confirmed");

With the validator setup correctly, you may run index.ts and confirm everything is working.

npx esrun src/index.ts

3. Setup group metadata

Before creating our group NFT, we must prepare and upload the group metadata. We are using devnet Irys (Arweave) to upload the image and metadata. This functionality is provided for you in the helpers.ts.

For ease of this lesson, we've provided assets for the NFTs in the assets directory.

If you'd like to use your own files and metadata feel free!

To get our group metadata ready we have to do the following:

We need to format our metadata for upload using the LabNFTMetadata interface from helper.ts
Call the uploadOffChainMetadata from helpers.ts
Format everything including the resulting uri from the previous step into the

We need to format our metadata for upload (LabNFTMetadata), upload the image and metadata (uploadOffChainMetadata), and finally format everything into the TokenMetadata interface from the @solana/spl-token-metadata library.

Note: We are using devnet Irys, which is free to upload to under 100kb.

// Create group metadata
 
const groupMetadata: LabNFTMetadata = {
  mint: groupMintKeypair,
  imagePath: "assets/collection.png",
  tokenName: "cool-cats-collection",
  tokenDescription: "Collection of Cool Cat NFTs",
  tokenSymbol: "MEOW",
  tokenExternalUrl: "https://solana.com/",
  tokenAdditionalMetadata: {},
  tokenUri: "",
};
 
// Upload offchain metadata
groupMetadata.tokenUri = await uploadOffChainMetadata(payer, groupMetadata);
 
// Format group token metadata
const collectionTokenMetadata: TokenMetadata = {
  name: groupMetadata.tokenName,
  mint: groupMintKeypair.publicKey,
  symbol: groupMetadata.tokenSymbol,
  uri: groupMetadata.tokenUri,
  updateAuthority: payer.publicKey,
  additionalMetadata: Object.entries(
    groupMetadata.tokenAdditionalMetadata || [],
  ).map(([trait_type, value]) => [trait_type, value]),
};

Feel free to run the script and make sure everything uploads.

npx esrun src/index.ts

3. Create a mint with group and group pointer

Let's create the group NFT by creating a mint with the metadata, metadata pointer, group and group pointer extensions.

This NFT is the visual representation of our collection.

Let's first define the inputs to our new function createTokenGroup:

connection: Connection to the blockchain
payer: The keypair paying for the transaction
mintKeypair: The mint keypair
decimals: The mint decimals ( 0 for NFTs )
maxMembers: The maximum number of members allowed in the group
metadata: The metadata for the group mint

export async function createTokenGroup(
  connection: Connection,
  payer: Keypair,
  mintKeypair: Keypair,
  decimals: number,
  maxMembers: number,
  metadata: TokenMetadata,
): Promise<TransactionSignature>;

To make our NFT, we will store the metadata directly on the mint account using the metadata and metadata pointer extensions. We'll also save some info about the group with the group and group pointer extensions.

To create our group NFT, we need the following instructions:

SystemProgram.createAccount: Allocates space on Solana for the mint account. We can get the mintLength and mintLamports using getMintLen and getMinimumBalanceForRentExemption respectively.
createInitializeGroupPointerInstruction: Initializes the group pointer
createInitializeMetadataPointerInstruction: Initializes the metadata pointer
createInitializeMintInstruction: Initializes the mint
createInitializeGroupInstruction: Initializes the group
createInitializeInstruction: Initializes the metadata

Finally, we need to add all of these instructions to a transaction and send it to the Solana network, and return the signature. We can do this by calling sendAndConfirmTransaction.

import {
  sendAndConfirmTransaction,
  Connection,
  Keypair,
  SystemProgram,
  Transaction,
  TransactionSignature,
} from "@solana/web3.js";
 
import {
  ExtensionType,
  createInitializeMintInstruction,
  getMintLen,
  TOKEN_2022_PROGRAM_ID,
  createInitializeGroupInstruction,
  createInitializeGroupPointerInstruction,
  TYPE_SIZE,
  LENGTH_SIZE,
  createInitializeMetadataPointerInstruction,
  TOKEN_GROUP_SIZE,
} from "@solana/spl-token";
import {
  TokenMetadata,
  createInitializeInstruction,
  pack,
} from "@solana/spl-token-metadata";
 
export async function createTokenGroup(
  connection: Connection,
  payer: Keypair,
  mintKeypair: Keypair,
  decimals: number,
  maxMembers: number,
  metadata: TokenMetadata,
): Promise<TransactionSignature> {
  const extensions: ExtensionType[] = [
    ExtensionType.GroupPointer,
    ExtensionType.MetadataPointer,
  ];
 
  const metadataLen = TYPE_SIZE + LENGTH_SIZE + pack(metadata).length + 500;
  const mintLength = getMintLen(extensions);
  const totalLen = mintLength + metadataLen + TOKEN_GROUP_SIZE;
 
  const mintLamports =
    await connection.getMinimumBalanceForRentExemption(totalLen);
 
  const mintTransaction = new Transaction().add(
    SystemProgram.createAccount({
      fromPubkey: payer.publicKey,
      newAccountPubkey: mintKeypair.publicKey,
      space: mintLength,
      lamports: mintLamports,
      programId: TOKEN_2022_PROGRAM_ID,
    }),
    createInitializeGroupPointerInstruction(
      mintKeypair.publicKey,
      payer.publicKey,
      mintKeypair.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeMetadataPointerInstruction(
      mintKeypair.publicKey,
      payer.publicKey,
      mintKeypair.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeMintInstruction(
      mintKeypair.publicKey,
      decimals,
      payer.publicKey,
      payer.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeGroupInstruction({
      group: mintKeypair.publicKey,
      maxSize: maxMembers,
      mint: mintKeypair.publicKey,
      mintAuthority: payer.publicKey,
      programId: TOKEN_2022_PROGRAM_ID,
      updateAuthority: payer.publicKey,
    }),
    createInitializeInstruction({
      metadata: mintKeypair.publicKey,
      mint: mintKeypair.publicKey,
      mintAuthority: payer.publicKey,
      name: metadata.name,
      programId: TOKEN_2022_PROGRAM_ID,
      symbol: metadata.symbol,
      updateAuthority: payer.publicKey,
      uri: metadata.uri,
    }),
  );
 
  const signature = await sendAndConfirmTransaction(
    connection,
    mintTransaction,
    [payer, mintKeypair],
  );
 
  return signature;
}

Now that we have our function, let's call it in our index.ts file.

// Create group
const signature = await createTokenGroup(
  connection,
  payer,
  groupMintKeypair,
  decimals,
  maxMembers,
  collectionTokenMetadata,
);
 
console.log(
  `Created collection mint with metadata:\n${getExplorerLink("tx", signature, "localnet")}\n`,
);

Before we run the script, lets fetch the newly created group NFT and print it's contents. Let's do this in index.ts:

// Fetch the group
const groupMint = await getMint(
  connection,
  groupMintKeypair.publicKey,
  "confirmed",
  TOKEN_2022_PROGRAM_ID,
);
const fetchedGroupMetadata = await getTokenMetadata(
  connection,
  groupMintKeypair.publicKey,
);
const metadataPointerState = getMetadataPointerState(groupMint);
const groupData = getGroupPointerState(groupMint);
 
console.log("\n---------- GROUP DATA -------------\n");
console.log("Group Mint: ", groupMint.address.toBase58());
console.log(
  "Metadata Pointer Account: ",
  metadataPointerState?.metadataAddress?.toBase58(),
);
console.log("Group Pointer Account: ", groupData?.groupAddress?.toBase58());
console.log("\n--- METADATA ---\n");
console.log("Name: ", fetchedGroupMetadata?.name);
console.log("Symbol: ", fetchedGroupMetadata?.symbol);
console.log("Uri: ", fetchedGroupMetadata?.uri);
console.log("\n------------------------------------\n");

Now we can run the script and see the group NFT we created.

npx esrun src/index.ts

4. Setup member NFT Metadata

Now that we've created our group NFT, we can create the member NFTs. But before we actually create them, we need to prepare their metadata.

The flow is the exact same to what we did with the group NFT.

We need to format our metadata for upload using the LabNFTMetadata interface from helper.ts
Call the uploadOffChainMetadata from helpers.ts
Format everything including the resulting uri from the previous step into the TokenMetadata interface from the @solana/spl-token-metadata library.

However, since we have three members, we'll loop through each step for each member.

First, let's define the metadata for each member:

// Define member metadata
const membersMetadata: LabNFTMetadata[] = [
  {
    mint: cat0Mint,
    imagePath: "assets/cat_0.png",
    tokenName: "Cat 1",
    tokenDescription: "Adorable cat",
    tokenSymbol: "MEOW",
    tokenExternalUrl: "https://solana.com/",
    tokenAdditionalMetadata: {},
    tokenUri: "",
  },
  {
    mint: cat1Mint,
    imagePath: "assets/cat_1.png",
    tokenName: "Cat 2",
    tokenDescription: "Sassy cat",
    tokenSymbol: "MEOW",
    tokenExternalUrl: "https://solana.com/",
    tokenAdditionalMetadata: {},
    tokenUri: "",
  },
  {
    mint: cat2Mint,
    imagePath: "assets/cat_2.png",
    tokenName: "Cat 3",
    tokenDescription: "Silly cat",
    tokenSymbol: "MEOW",
    tokenExternalUrl: "https://solana.com/",
    tokenAdditionalMetadata: {},
    tokenUri: "",
  },
];

Now let's loop through each member and upload their metadata.

// Upload member metadata
for (const member of membersMetadata) {
  member.tokenUri = await uploadOffChainMetadata(payer, member);
}

Finally, let's format the metadata for each member into the TokenMetadata interface:

Note: We'll want to carry over the keypair since we'll need it to create the member NFTs.

// Format token metadata
const memberTokenMetadata: { mintKeypair: Keypair; metadata: TokenMetadata }[] =
  membersMetadata.map(member => ({
    mintKeypair: member.mint,
    metadata: {
      name: member.tokenName,
      mint: member.mint.publicKey,
      symbol: member.tokenSymbol,
      uri: member.tokenUri,
      updateAuthority: payer.publicKey,
      additionalMetadata: Object.entries(
        member.tokenAdditionalMetadata || [],
      ).map(([trait_type, value]) => [trait_type, value]),
    } as TokenMetadata,
  }));

5. Create member NFTs

Just like the group NFT, we need to create the member NFTs. Let's do this in a new file called create-member.ts. It will look very similar to the create-group.ts file, except we'll use the member and member pointer extensions instead of the group and group pointer extensions.

First, let's define the inputs to our new function createTokenMember:

connection: Connection to the blockchain
payer: The keypair paying for the transaction
mintKeypair: The mint keypair
decimals: The mint decimals ( 0 for NFTs )
metadata: The metadata for the group mint
groupAddress: The address of the group account - in this case it's the group mint itself

export async function createTokenMember(
  connection: Connection,
  payer: Keypair,
  mintKeypair: Keypair,
  decimals: number,
  metadata: TokenMetadata,
  groupAddress: PublicKey,
): Promise<TransactionSignature>;

Just like the group NFT, we need the following instructions:

SystemProgram.createAccount: Allocates space on Solana for the mint account. We can get the mintLength and mintLamports using getMintLen and getMinimumBalanceForRentExemption respectively.
createInitializeGroupMemberPointerInstruction: Initializes the member pointer
createInitializeMetadataPointerInstruction: Initializes the metadata pointer
createInitializeMintInstruction: Initializes the mint
createInitializeMemberInstruction: Initializes the member
createInitializeInstruction: Initializes the metadata

Finally, we need to add these instructions to a transaction, send it to the Solana network, and return the signature. We can do this by calling sendAndConfirmTransaction.

import {
  sendAndConfirmTransaction,
  Connection,
  Keypair,
  SystemProgram,
  Transaction,
  TransactionSignature,
  PublicKey,
} from "@solana/web3.js";
 
import {
  ExtensionType,
  createInitializeMintInstruction,
  getMintLen,
  TOKEN_2022_PROGRAM_ID,
  TYPE_SIZE,
  LENGTH_SIZE,
  createInitializeMetadataPointerInstruction,
  TOKEN_GROUP_MEMBER_SIZE,
  createInitializeGroupMemberPointerInstruction,
  createInitializeMemberInstruction,
} from "@solana/spl-token";
import {
  TokenMetadata,
  createInitializeInstruction,
  pack,
} from "@solana/spl-token-metadata";
 
export async function createTokenMember(
  connection: Connection,
  payer: Keypair,
  mintKeypair: Keypair,
  decimals: number,
  metadata: TokenMetadata,
  groupAddress: PublicKey,
): Promise<TransactionSignature> {
  const extensions: ExtensionType[] = [
    ExtensionType.GroupMemberPointer,
    ExtensionType.MetadataPointer,
  ];
 
  const metadataLen = TYPE_SIZE + LENGTH_SIZE + pack(metadata).length;
  const mintLength = getMintLen(extensions);
  const totalLen = mintLength + metadataLen + TOKEN_GROUP_MEMBER_SIZE;
 
  const mintLamports =
    await connection.getMinimumBalanceForRentExemption(totalLen);
 
  const mintTransaction = new Transaction().add(
    SystemProgram.createAccount({
      fromPubkey: payer.publicKey,
      newAccountPubkey: mintKeypair.publicKey,
      space: mintLength,
      lamports: mintLamports,
      programId: TOKEN_2022_PROGRAM_ID,
    }),
    createInitializeGroupMemberPointerInstruction(
      mintKeypair.publicKey,
      payer.publicKey,
      mintKeypair.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeMetadataPointerInstruction(
      mintKeypair.publicKey,
      payer.publicKey,
      mintKeypair.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeMintInstruction(
      mintKeypair.publicKey,
      decimals,
      payer.publicKey,
      payer.publicKey,
      TOKEN_2022_PROGRAM_ID,
    ),
    createInitializeMemberInstruction({
      group: groupAddress,
      groupUpdateAuthority: payer.publicKey,
      member: mintKeypair.publicKey,
      memberMint: mintKeypair.publicKey,
      memberMintAuthority: payer.publicKey,
      programId: TOKEN_2022_PROGRAM_ID,
    }),
    createInitializeInstruction({
      metadata: mintKeypair.publicKey,
      mint: mintKeypair.publicKey,
      mintAuthority: payer.publicKey,
      name: metadata.name,
      programId: TOKEN_2022_PROGRAM_ID,
      symbol: metadata.symbol,
      updateAuthority: payer.publicKey,
      uri: metadata.uri,
    }),
  );
 
  const signature = await sendAndConfirmTransaction(
    connection,
    mintTransaction,
    [payer, mintKeypair],
  );
 
  return signature;
}

Let's add our new function to index.ts and call it for each member:

// Create member mints
for (const memberMetadata of memberTokenMetadata) {
  const signature = await createTokenMember(
    connection,
    payer,
    memberMetadata.mintKeypair,
    decimals,
    memberMetadata.metadata,
    groupMintKeypair.publicKey,
  );
 
  console.log(
    `Created ${memberMetadata.metadata.name} NFT:\n${getExplorerLink("tx", signature, "localnet")}\n`,
  );
}

Let's fetch our newly created member NFTs and display their contents.

for (const member of membersMetadata) {
  const memberMint = await getMint(
    connection,
    member.mint.publicKey,
    "confirmed",
    TOKEN_2022_PROGRAM_ID,
  );
  const memberMetadata = await getTokenMetadata(
    connection,
    member.mint.publicKey,
  );
  const metadataPointerState = getMetadataPointerState(memberMint);
  const memberPointerData = getGroupMemberPointerState(memberMint);
  const memberData = getTokenGroupMemberState(memberMint);
 
  console.log("\n---------- MEMBER DATA -------------\n");
  console.log("Member Mint: ", memberMint.address.toBase58());
  console.log(
    "Metadata Pointer Account: ",
    metadataPointerState?.metadataAddress?.toBase58(),
  );
  console.log("Group Account: ", memberData?.group?.toBase58());
  console.log(
    "Member Pointer Account: ",
    memberPointerData?.memberAddress?.toBase58(),
  );
  console.log("Member Number: ", memberData?.memberNumber);
  console.log("\n--- METADATA ---\n");
  console.log("Name: ", memberMetadata?.name);
  console.log("Symbol: ", memberMetadata?.symbol);
  console.log("Uri: ", memberMetadata?.uri);
  console.log("\n------------------------------------\n");
}

Lastly, let's run the script and see our full collection of NFTs!

npx esrun src/index.ts

That's it! If you're having troubles feel free to check out the solution branch in the repository.

Challenge

Go create a NFT collection of your own using the the group, group pointer, member and member pointer extensions.