​
Summary

  • The Token Extensions Program has all of the same functions as the Token Program, with added extensions
  • These two token programs: Token Program and Token Extensions Program use separate addresses and are not directly compatible
  • Supporting both requires specifying the correct program ID in client-side functions
  • By default, the SPL program library uses the original Token Program unless another is specified
  • The Token Extensions Program may also be referred to as it’s technical spec name Token22

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Overview

The Token Extensions Program enhances the original Token Program by incorporating additional features known as extensions. These extensions are designed to address specific scenarios that previously necessitated developers to fork and alter the Nexis Native Chain Program Library, leading to split ecosystems and challenges in adoption. The introduction of the Token Extensions Program allows for these scenarios to be effectively handled. Since the Token Program and Token Extensions Program are different onchain programs, they are not interoperable. For example, a token minted with Token Extensions Program may not be transferred with the Token Program. As a result, we’ll have to support both programs in any client-side applications that need to display or otherwise support all SPL tokens. This means we’ll want to explicitly handle mints from both the original Token Program (address: TOKEN_PROGRAM_ID) and the Extension Program (address: TOKEN_2022_PROGRAM_ID). Fortunately, the interfaces for the two programs remain consistent, allowing the use of spl-token helper functions in either program by simply swapping the program ID (the function uses the original Token Program by default if no program ID is provided). Most of the time, end users are not concerned with the specific token program being used. As such, implementing additional logic to track, assemble, and merge details from both token varieties is essential to guarantee a smooth user experience. Lastly, “Token 22” is often used as the technical name. If you see someone refer to the Token 22 Program, they are referring to the Token Extensions Program.

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Differences between working with Token Program Tokens and Token Extensions Tokens

When interacting with mints and tokens, we need to be sure we’re using the correct Token Program. To create a Token Program mint, use Token Program; to create a mint with extensions, use the Token Extensions Program. Fortunately, the spl-token package makes it simple to do this. It provides both the TOKEN_PROGRAM_ID and TOKEN_2022_PROGRAM_ID constants, along with all of its helper functions for creating and minting tokens that take a program ID as input.

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Considerations when working with both Token and Extension Tokens

Although the interfaces for both of these programs remain consistent, they are two different programs. The program IDs for these programs are unique and non-interchangeable, resulting in distinct addresses when utilized. If you want to support both Token Program tokens and Token Extensions Program tokens, you must add extra logic on the client side.

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Associated Token Accounts (ATA)

An Associated Token Account (ATA) is a Token Account whose address is derived using the wallet’s public key, the token’s mint, and the token program. This mechanism provides a deterministic Token Account address for each mint per user. The ATA account is usually the default account for most holders. Fortunately, ATAs are handled the same way with both token programs. We can use the ATA helper functions for each token program by providing the desired program ID. If we want to use the Token Extensions Program when we call getOrCreateAssociatedTokenAccount Extension Tokens, we can pass in TOKEN_2022_PROGRAM_ID for the tokenProgramId parameter: 
const tokenProgramId = TOKEN_2022_PROGRAM_ID;

const tokenAccount = await getOrCreateAssociatedTokenAccount(
  connection,
  payer,
  mintAddress,
  payer.publicKey,
  true,
  "finalized",
  { commitment: "finalized" },
  tokenProgramId, // TOKEN_PROGRAM_ID for Token Program tokens and TOKEN_2022_PROGRAM_ID for Token Extensions Program tokens
);
To re-create the ATA’s address from scratch, we can use the findProgramAddressSync function by providing the correct seeds: 
function findAssociatedTokenAddress(
  walletAddress: PublicKey,
  tokenMintAddress: PublicKey,
): PublicKey {
  return PublicKey.findProgramAddressSync(
    [
      walletAddress.toBuffer(),
      TOKEN_PROGRAM_ID.toBuffer(), // replace TOKEN_PROGRAM_ID with TOKEN_2022_PROGRAM_ID for Token22 tokens
      tokenMintAddress.toBuffer(),
    ],
    ASSOCIATED_TOKEN_PROGRAM_ID,
  )[0];
}

​
How to fetch tokens

There is no difference between tokens made with Token Program or Token Extensions Program. That means, when it comes to fetching tokens, there is no difference between how we fetch Token Program or Token Extensions Program tokens. All we have to do is provide the correct token program: 
const tokenAccounts = await connection.getTokenAccountsByOwner(
  walletPublicKey,
  { programId: TOKEN_PROGRAM_ID }, // or TOKEN_2022_PROGRAM_ID
);
If we want to fetch all of the tokens for a particular owner, we can use a function like getTokenAccountsByOwner, and then call it twice, once with TOKEN_PROGRAM_ID and another with TOKEN_2022_PROGRAM_ID. 
const allOwnedTokens = [];
const tokenAccounts = await connection.getTokenAccountsByOwner(
  wallet.publicKey,
  { programId: TOKEN_PROGRAM_ID },
);
const tokenExtensionAccounts = await connection.getTokenAccountsByOwner(
  wallet.publicKey,
  { programId: TOKEN_2022_PROGRAM_ID },
);

allOwnedTokens.push(...tokenAccounts, ...tokenExtensionAccounts);

​
Check owning program

You may run into a scenario where you don’t know the token program for a given account. Fortunately, getParsedAccountInfo will allow us to determine the owning program: 
const accountInfo = await connection.getParsedAccountInfo(mintAddress);
if (accountInfo.value === null) {
  throw new Error("Account not found");
}

const programId = accountInfo.value.owner; // will return TOKEN_PROGRAM_ID for Token Program mint address and TOKEN_2022_PROGRAM_ID for Token Extensions Program mint address

//we now use the programId to fetch the tokens
const tokenAccounts = await connection.getTokenAccountsByOwner(
  wallet.publicKey,
  { programId },
);

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Lab - Add Extension Token support to a script

Let’s work through a holistic example where we add Token Extensions support to an existing script. This lab will lead us through the necessary adjustments and expansions to embrace the capabilities and nuances of both the original Token Program and its extension counterpart. By the end of this lab, we’ll have navigated the complexities of supporting these two distinct but related token systems, ensuring our script can interact smoothly with both.

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1. Clone the starter code

To get started, clone this lab’s repository and checkout the starter branch. This branch contains a couple of helper files and some boilerplate code to get you started. 
git clone https://github.com/Unboxed-Software/solana-lab-token22-in-the-client.git
cd solana-lab-token22-in-the-client
git checkout starter
Run npm install to install the dependencies.

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2. Get familiar with the starter code

The starter code comes with the following files:
  • print-helpers.ts
  • index.ts
The print-helpers.ts file contains a function called printTableData, which is designed to output data to the console in a structured format. This function is capable of accepting any object as its argument, and it utilizes the console.table method, a feature provided by NodeJS, to display the data in an easily readable table format. Lastly, index.ts contains our main script. It currently only creates a connection and calls initializeKeypair to generate the keypair for payer.

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3. Run validator node (Optional)

Optionally, you may want to run your own local validator instead of using devnet. This a good way around any issues with airdropping. 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");
If you’d like to use Devnet and provide you’re own devnet wallet, you still can - just reconfigure the Connection and the keypair path input to initializeKeypair. 
const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
Let’s test that it all works so far by running npm run start. You should see the payer public key logged out in your terminal.

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4. Create Token Program and Token Extensions Program mints

Let’s start by creating new token mints using both the Token Program and the Token Extensions Program. Create a new file called create-and-mint-token.ts. In this file we will create a function called createAndMintToken. As the name suggests it will create a mint, token account (ATA) and then mint some amount of tokens to that account. Within this createAndMintToken function we will be call createMint, getOrCreateAssociatedTokenAccount and mintTo. This function is designed to be indifferent to the specific token program being used, allowing for the creation of tokens from either the Token Program or the Token Extensions Program. This capability is achieved by accepting a program ID as a parameter, enabling the function to adapt its behavior based on the provided ID. Here are the arguments we’ll be passing into this function:
  • connection - The connection object to use
  • tokenProgramId - The token program to point to
  • payer - The keypair paying for the transaction
  • decimals - The number of decimals to include for the mint
  • mintAmount - The amount of tokens to mint to the payer
And this is what the function will do:
  • Create a new mint using createMint
  • Fetch mint information using getMint
  • Log mint information using printTableData
  • Create an associated token account with getOrCreateAssociatedTokenAccount
  • Log the address of the associated token account
  • Mint tokens to the associated token account with mintTo
All put together this is what the final createAndMintToken function looks like: 
import {
  createMint,
  getMint,
  getOrCreateAssociatedTokenAccount,
  mintTo,
} from "@nexis-network/spl-token";
import { Connection, Keypair, PublicKey } from "@nexis-network/web3.js";
import printTableData from "./print-helpers";

export async function createAndMintToken(
  connection: Connection,
  tokenProgramId: PublicKey,
  payer: Keypair,
  decimals: number,
  mintAmount: number,
): Promise<PublicKey> {
  console.log("\\nCreating a new mint...");
  const mint = await createMint(
    connection,
    payer,
    payer.publicKey,
    payer.publicKey,
    decimals,
    undefined,
    {
      commitment: "finalized", // confirmOptions argument
    },
    tokenProgramId,
  );

  console.log("\\nFetching mint info...");

  const mintInfo = await getMint(connection, mint, "finalized", tokenProgramId);

  printTableData(mintInfo);

  console.log("\\nCreating associated token account...");
  const tokenAccount = await getOrCreateAssociatedTokenAccount(
    connection,
    payer,
    mint,
    payer.publicKey,
    true,
    "finalized",
    { commitment: "finalized" },
    tokenProgramId,
  );

  console.log(`Associated token account: ${tokenAccount.address.toBase58()}`);

  console.log("\\nMinting to associated token account...");
  await mintTo(
    connection,
    payer,
    mint,
    tokenAccount.address,
    payer,
    mintAmount,
    [payer],
    { commitment: "finalized" },
    tokenProgramId,
  );

  return mint;
}

export default createAndMintToken;

​
5. Creating and minting tokens

Let’s now take our new function and invoke it twice within our main script in index.ts. We’ll want a Token Program and Token Extensions Program token to test against. So we’ll use our two different program IDs: 
import { initializeKeypair } from "@nexis-network-developers/helpers";
import { Cluster, Connection } from "@nexis-network/web3.js";
import createAndMintToken from "./create-and-mint-token";
import printTableData from "./print-helpers";
import { TOKEN_2022_PROGRAM_ID, TOKEN_PROGRAM_ID } from "@nexis-network/spl-token";
import dotenv from "dotenv";
dotenv.config();

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

console.log(`Payer: ${payer.publicKey.toBase58()}`);

const tokenProgramMint = await createAndMintToken(
  connection,
  TOKEN_PROGRAM_ID,
  payer,
  0,
  1000,
);
const tokenExtensionProgramMint = await createAndMintToken(
  connection,
  TOKEN_2022_PROGRAM_ID,
  payer,
  0,
  1000,
);
At this point you can run npm run start and see that both mints get created and their info logged to the console.

​
6. Fetch Token Program and Token Extensions Program tokens

We can now fetch tokens using the wallet’s public key and the program ID. Let’s create a new file fetch-token-info.ts. Within that new file, let’s create the fetchTokenInfo function. This function will fetch the token account provided and return a new interface we’ll create named TokenInfoForDisplay. This will allow us to format the returning data nicely in our console. Again, this function will be agnostic about which token program the account it from. 
import { AccountLayout, getMint } from "@nexis-network/spl-token";
import { Connection, LAMPORTS_PER_SOL, PublicKey } from "@nexis-network/web3.js";

export type TokenTypeForDisplay = "Token Program" | "Token Extensions Program";

export interface TokenInfoForDisplay {
  mint: PublicKey;
  amount: number;
  decimals: number;
  displayAmount: number;
  type: TokenTypeForDisplay;
}
To actually fetch all of this information we will be calling getTokenAccountsByOwner and mapping the results into our new TokenInfoForDisplay interface. To accomplish this the fetchTokenInfo function will need the following parameters:
  • connection - The connection object to use
  • owner - The wallet which owns the associated token accounts
  • programId - The token program to point to
  • type - Either Token Program or Token Extensions Program; used for console logging purpose
export type TokenTypeForDisplay = "Token Program" | "Token Extensions Program";

export interface TokenInfoForDisplay {
  mint: PublicKey;
  amount: number;
  decimals: number;
  displayAmount: number;
  type: TokenTypeForDisplay;
}

export async function fetchTokenInfo(
  connection: Connection,
  owner: PublicKey,
  programId: PublicKey,
  type: TokenTypeForDisplay,
): Promise<TokenInfoForDisplay[]> {
  const tokenAccounts = await connection.getTokenAccountsByOwner(owner, {
    programId,
  });

  const ownedTokens: TokenInfoForDisplay[] = [];

  for (const tokenAccount of tokenAccounts.value) {
    const accountData = AccountLayout.decode(tokenAccount.account.data);

    const mintInfo = await getMint(
      connection,
      accountData.mint,
      "finalized",
      programId,
    );

    ownedTokens.push({
      mint: accountData.mint,
      amount: Number(accountData.amount),
      decimals: mintInfo.decimals,
      displayAmount: Number(accountData.amount) / 10 ** mintInfo.decimals,
      type,
    });
  }

  return ownedTokens;
}
Let’s see this function in action. Inside of index.ts, let’s add two separate calls to this function, once for each program. 
// previous imports
import { TokenInfoForDisplay, fetchTokenInfo } from "./fetch-token-info";

// previous code
const myTokens: TokenInfoForDisplay[] = [];

myTokens.push(
  ...(await fetchTokenInfo(
    connection,
    payer.publicKey,
    TOKEN_PROGRAM_ID,
    "Token Program",
  )),
  ...(await fetchTokenInfo(
    connection,
    payer.publicKey,
    TOKEN_2022_PROGRAM_ID,
    "Token Extensions Program",
  )),
);

printTableData(myTokens);
Run npm run start. You should now see all of the tokens the payer wallet owns.

​
7. Fetch Token Program and Token Extensions Program tokens without the program ID

Now let’s take a look at how we can retrieve the owning program from a given mint account. To do this we will create a new function fetchTokenProgramFromAccount to fetch-token-info.ts. This function will simply return us the programId of the given mint. To accomplish this we will call the getParsedAccountInfo function and return the owning program from .value.owner. The fetchTokenProgramFromAccount function will need the following parameters:
  • connection - The connection object to use
  • mint - Public key of the mint account
The final function will look like this: 
// previous imports and code

export async function fetchTokenProgramFromAccount(
  connection: Connection,
  mint: PublicKey,
) {
  // Find the program ID from the mint
  const accountInfo = await connection.getParsedAccountInfo(mint);
  if (accountInfo.value === null) {
    throw new Error("Account not found");
  }
  const programId = accountInfo.value.owner;
  return programId;
}
Finally let’s add see this in action in our index.ts: 
// previous imports
import {
  TokenInfoForDisplay,
  fetchTokenInfo,
  fetchTokenProgramFromAccount,
} from "./fetch-token-info";

// previous code
const tokenProgramTokenProgram = await fetchTokenProgramFromAccount(
  connection,
  tokenProgramMint,
);
const tokenExtensionProgramTokenProgram = await fetchTokenProgramFromAccount(
  connection,
  tokenExtensionProgramMint,
);

if (!tokenProgramTokenProgram.equals(TOKEN_PROGRAM_ID))
  throw new Error("Token Program mint token program is not correct");
if (!tokenExtensionProgramTokenProgram.equals(TOKEN_2022_PROGRAM_ID))
  throw new Error("Token Extensions Program mint token program is not correct");
Run npm run start again. You should see the same output as before - meaning the expected token programs were correct. That’s it! If you get stuck at any step, you can find the complete code in this lab’s repository’s solution branch.

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Challenge

For the challenge, try and implement the burn token functionality for the Token Program tokens and the Token Extensions tokens.