token-utils: Add helper to mint a NFT (#217)

* token-utils: Add helper to mint a NFT

* mintAuthority -> tempMintAuthority

packages/token-utils/src/instructions/nft.ts

@@ -0,0 +1,55 @@
+import type { Provider, TransactionEnvelope } from "@saberhq/solana-contrib";
+import { Token as SPLToken, TOKEN_PROGRAM_ID, u64 } from "@solana/spl-token";
+import type { PublicKey, Signer } from "@solana/web3.js";
+
+import { createInitMintInstructions, getOrCreateATA } from ".";
+
+export const mintNFT = async (
+  provider: Provider,
+  mintKP: Signer,
+  owner: PublicKey = provider.wallet.publicKey
+): Promise<TransactionEnvelope> => {
+  // Temporary mint authority
+  const tempMintAuthority = provider.wallet.publicKey;
+  // Mint for the NFT
+  const tx = await createInitMintInstructions({
+    provider,
+    mintKP,
+    decimals: 0,
+    mintAuthority: tempMintAuthority,
+  });
+  // Token account for the NFT
+  const { address, instruction } = await getOrCreateATA({
+    provider,
+    mint: mintKP.publicKey,
+    owner: owner,
+    payer: provider.wallet.publicKey,
+  });
+  if (instruction) {
+    tx.instructions.push(instruction);
+  }
+  // Mint to owner's ATA
+  tx.instructions.push(
+    SPLToken.createMintToInstruction(
+      TOKEN_PROGRAM_ID,
+      mintKP.publicKey,
+      address,
+      tempMintAuthority,
+      [],
+      new u64(1)
+    )
+  );
+  // Set mint authority of the NFT to NULL
+  tx.instructions.push(
+    SPLToken.createSetAuthorityInstruction(
+      TOKEN_PROGRAM_ID,
+      mintKP.publicKey,
+      null,
+      "MintTokens",
+      tempMintAuthority,
+      []
+    )
+  );
+
+  return tx;
+};