TransactionModifyingSigner

type TransactionModifyingSigner<TAddress> = Readonly<{
  address: Address<TAddress>;
  modifyAndSignTransactions: Promise<readonly Readonly<{
     messageBytes: TransactionMessageBytes;
     signatures: SignaturesMap;
  }> & TransactionWithinSizeLimit & TransactionWithLifetime[]>;
}>;

A signer interface that potentially modifies the provided Transaction | Transactions before signing them.

For instance, this enables wallets to inject additional instructions into the transaction before signing them. For each transaction, instead of returning a SignatureDictionary, its TransactionModifyingSigner#modifyAndSignTransactions | modifyAndSignTransactions function returns an updated Transaction with a potentially modified set of instructions and signature dictionary. The returned transaction must be within the transaction size limit, and include a lifetimeConstraint.

Type Parameters

Example

const signer: TransactionModifyingSigner<'1234..5678'> = {
    address: address('1234..5678'),
    modifyAndSignTransactions: async (
        transactions: Transaction[]
    ): Promise<(Transaction & TransactionWithinSizeLimit & TransactionWithLifetime)[]> => {
        // My custom signing logic.
    },
};

Remarks

Here are the main characteristics of this signer interface:

• Sequential. Contrary to partial signers, these cannot be executed in parallel as each call can modify the provided transactions.
• First signers. For a given transaction, a modifying signer must always be used before a partial signer as the former will likely modify the transaction and thus impact the outcome of the latter.
• Potential conflicts. If more than one modifying signer is provided, the second signer may invalidate the signature of the first one. However, modifying signers may decide not to modify a transaction based on the existence of signatures for that transaction.

See

• isTransactionModifyingSigner
• assertIsTransactionModifyingSigner