How to Create a Token

import {
  clusterApiUrl,
  Connection,
  Keypair,
  sendAndConfirmTransaction,
  SystemProgram,
  Transaction,
} from "@solana/web3.js";
import {
  createInitializeMintInstruction,
  TOKEN_PROGRAM_ID,
  MINT_SIZE,
  getMinimumBalanceForRentExemptMint,
  createMint,
} from "@solana/spl-token";
import bs58 from "bs58";

(async () => {
  // connection
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const recentBlockhash = await connection.getLatestBlockhash();

  // 5YNmS1R9nNSCDzb5a7mMJ1dwK9uHeAAF4CmPEwKgVWr8
  const feePayer = Keypair.fromSecretKey(
    bs58.decode(
      "588FU4PktJWfGfxtzpAAXywSNt74AvtroVzGfKkVN1LwRuvHwKGr851uH8czM5qm4iqLbs1kKoMKtMJG4ATR7Ld2",
    ),
  );

  // G2FAbFQPFa5qKXCetoFZQEvF9BVvCKbvUZvodpVidnoY
  const alice = Keypair.fromSecretKey(
    bs58.decode(
      "4NMwxzmYj2uvHuq8xoqhY8RXg63KSVJM1DXkpbmkUY7YQWuoyQgFnnzn6yo3CMnqZasnNPNuAT2TLwQsCaKkUddp",
    ),
  );

  // 1) use build-in function
  let mintPubkey = await createMint(
    connection, // connection
    feePayer, // fee payer
    alice.publicKey, // mint authority
    alice.publicKey, // freeze authority (you can use `null` to disable it. when you disable it, you can't turn it on again)
    8, // decimals
  );
  console.log(`mint: ${mintPubkey.toBase58()}`);

  // or

  // 2) compose by yourself
  const mint = Keypair.generate();
  console.log(`mint: ${mint.publicKey.toBase58()}`);

  const transaction = new Transaction().add(
    // create mint account
    SystemProgram.createAccount({
      fromPubkey: feePayer.publicKey,
      newAccountPubkey: mint.publicKey,
      space: MINT_SIZE,
      lamports: await getMinimumBalanceForRentExemptMint(connection),
      programId: TOKEN_PROGRAM_ID,
    }),
    // init mint account
    createInitializeMintInstruction(
      mint.publicKey, // mint pubkey
      8, // decimals
      alice.publicKey, // mint authority
      alice.publicKey, // freeze authority (you can use `null` to disable it. when you disable it, you can't turn it on again)
    ),
  );

  // Send transaction
  const transactionSignature = await sendAndConfirmTransaction(
    connection,
    transaction,
    [feePayer, mint], // Signers
  );

  console.log(`txhash: ${transactionSignature}`);
})();