sendAndConfirmTransaction returns Cannot read properties of undefined (reading 'toString')

Question

I cannot send the transaction here. Tried using wallet-adapter methods as well as solana/web3js methods, tried separating sendTransaction and confirmTransaction. Similar "cannot read .toString() of undefined" error for all the methods but at different places in the module.

Code

  const { connection } = useConnection();
  const wallet = useWallet();
  const burnAndSendSol = async () => {
    const associatedAddress = await getAssociatedTokenAddress(
      ASSOCIATED_TOKEN_PROGRAM_ID,
      TOKEN_PROGRAM_ID,
      mintPublickey,
      publicKey
    );

    const burnInstruction = createBurnCheckedInstruction(
      associatedAddress,
      mintPublickey,
      publicKey,
      1,
      TOKEN_PROGRAM_ID
    );

    const burnAndTransferTransaction = new Transaction().add(
      burnInstruction,
      SystemProgram.transfer({
        fromPubkey: publicKey,
        toPubkey: vaultPubKey,
        lamports: 0.5 * LAMPORTS_PER_SOL,
      })
    );

    try {
      const txn = await sendAndConfirmTransaction(
        connection,
        burnAndTransferTransaction,
        [wallet]
      );
    } catch (error) {
      console.log(error);
    }
  }

Error Stacktrace

TypeError: Cannot read properties of undefined (reading 'toString')
    at eval (index.browser.esm.js?156f:2629:1)
    at Array.forEach (<anonymous>)
    at Transaction.compileMessage (index.browser.esm.js?156f:2628:1)
    at Transaction._compile (index.browser.esm.js?156f:2749:1)
    at Transaction.sign (index.browser.esm.js?156f:2854:1)
    at Connection.sendTransaction (index.browser.esm.js?156f:7386:1)
    at async sendAndConfirmTransaction (index.browser.esm.js?156f:3130:1)

Answer 1

Presuming that useWallet() is from @solana/wallet-adapter, its return value is not a Signer.

The return value of useWallet is a WalletContextState.

WalletContextState does not expose the private key you would need to sign a transaction, as your code is currently written to do. Rather, use the methods returned by useWallet to send the transaction through the currently connected wallet.

const {sendTransaction} = useWallet();
const burnAndSendSol = useCallback(async () => {
  /* ... */
  try {
    const signature = sendTransaction(
      burnAndTransferTransaction,
      connection,
    );
    await connection.confirmTransaction(signature);
  } catch (e) {
    console.log(e);
  }
}, [sendTransaction]);

Answer 2

I found the solution and turns out it was just a rookie mistake on my side.

The mintPublicKey I was passing to the "getAssociatedAddress" function was the mint address in the string form instead of the PublicKey form, no wonder .toString() could not be called on it.

const mintPublicKey = new PublicKey(mintAddresss);

and passing mintPublicKey to getAssociatedAddress solved the issue.