How to sign anchor transactions with phantom or other wallets in the browser

#solana #anchor #phantom #blockchain

If you've tried using the (solana) anchor rpc convenience instructions, to avoid assembling your accounts and everything into a buffer explicitly, and used a browser wallet as a signer:

// Wrong!
await program.rpc.stake(
    myArgs,
    {
        accounts: {
            account1,
            account2,
        },
        signers: [wallet],
    }
)

Then you've probably gotten this error, because the browser wallet doesn't hand out its secret key:

Uncaught (in promise) TypeError: unexpected type, use Uint8Array

Instead, you can use program.transaction to make the transaction, then ask the wallet to sign it:

const tx = program.transaction.myInstruction(
    myArgs,
    {
        accounts: {
            account1,
            account2,
        },
        signers: [],
    }
)
tx.feePayer = wallet.publicKey
tx.recentBlockhash = (await connection.getLatestBlockhash()).blockhash
const signedTx = await wallet.signTransaction(tx)
const txId = await connection.sendRawTransaction(signedTx.serialize())
await connection.confirmTransaction(txId)