Attaching metadata

Ref -

1. https://github.com/100xdevs-cohort-3/week-6-web3-token-launchpad/tree/main/4-token-launchpage-with-metadata
2. https://solana.com/developers/guides/token-extensions/metadata-pointer
3. Convert the mint to use token 2022 program
4. After creating the token, create the metadata

Ref - https://spl.solana.com/token-2022/extensions#example-create-a-mint-with-metadata

Using the token22 program, let’s create the mint with some metadata

import { Keypair, SystemProgram, Transaction } from "@solana/web3.js";
import { useConnection, useWallet } from '@solana/wallet-adapter-react';
import { TOKEN_2022_PROGRAM_ID, getMintLen, createInitializeMetadataPointerInstruction, createInitializeMintInstruction, TYPE_SIZE, LENGTH_SIZE, ExtensionType } from "@solana/spl-token"
import { createInitializeInstruction, pack } from '@solana/spl-token-metadata';

export function TokenLaunchpad() {
    const { connection } = useConnection();
    const wallet = useWallet();

    async function createToken() {
        const mintKeypair = Keypair.generate();
        const metadata = {
            mint: mintKeypair.publicKey,
            name: 'KIRA',
            symbol: 'KIR    ',
            uri: 'https://cdn.100xdevs.com/metadata.json',
            additionalMetadata: [],
        };

        const mintLen = getMintLen([ExtensionType.MetadataPointer]);
        const metadataLen = TYPE_SIZE + LENGTH_SIZE + pack(metadata).length;

        const lamports = await connection.getMinimumBalanceForRentExemption(mintLen + metadataLen);

        const transaction = new Transaction().add(
            SystemProgram.createAccount({
                fromPubkey: wallet.publicKey,
                newAccountPubkey: mintKeypair.publicKey,
                space: mintLen,
                lamports,
                programId: TOKEN_2022_PROGRAM_ID,
            }),
            createInitializeMetadataPointerInstruction(mintKeypair.publicKey, wallet.publicKey, mintKeypair.publicKey, TOKEN_2022_PROGRAM_ID),
            createInitializeMintInstruction(mintKeypair.publicKey, 9, wallet.publicKey, null, TOKEN_2022_PROGRAM_ID),
            createInitializeInstruction({
                programId: TOKEN_2022_PROGRAM_ID,
                mint: mintKeypair.publicKey,
                metadata: mintKeypair.publicKey,
                name: metadata.name,
                symbol: metadata.symbol,
                uri: metadata.uri,
                mintAuthority: wallet.publicKey,
                updateAuthority: wallet.publicKey,
            }),
        );

        transaction.feePayer = wallet.publicKey;
        transaction.recentBlockhash = (await connection.getLatestBlockhash()).blockhash;
        transaction.partialSign(mintKeypair);

        await wallet.sendTransaction(transaction, connection);
    }

    return <div style={{
        height: '100vh',
        display: 'flex',
        justifyContent: 'center',
        alignItems: 'center',
        flexDirection: 'column'
    }}>
        <h1>Solana Token Launchpad</h1>
        <input className='inputText' type='text' placeholder='Name'></input> <br />
        <input className='inputText' type='text' placeholder='Symbol'></input> <br />
        <input className='inputText' type='text' placeholder='Image URL'></input> <br />
        <input className='inputText' type='text' placeholder='Initial Supply'></input> <br />
        <button onClick={createToken} className='btn'>Create a token</button>
    </div>
}