Cardano HW Interoperability Library

JavaScript library to validate and transform Cardano transactions according to CIP-0021.

Available methods

The provided functions operate on either a:

• transaction body - only the transaction body as defined in the CDDL
• transaction - as defined in the CDDL or outputted by cardano-cli transaction build-raw

decode

Parses a CBOR encoded input into a TransactionBody or Transaction, respectively. If the CBOR is malformed the parser will throw an error. Available methods:

decodeTxBody(txBodyCbor: Buffer) => TransactionBody
decodeTx(txCbor: Buffer) => Transaction

The TransactionBody object mostly follows the CDDL, but sometimes makes small deviations for better developer experience, such as parsing certain tuples as objects, or maps as arrays because working with maps is cumbersome in JavaScript.

When parsing a transaction, fields other than the transaction body are only decoded from CBOR and are not parsed according to the CDDL, in TypeScript they have type unknown.

encode

Takes a TransactionBody or Transaction object and encodes it back to CBOR using canonical CBOR serialization format as specified in Section 3.9 of CBOR RFC. Available methods:

encodeTxBody(txBody: TransactionBody) => Buffer
encodeTx(tx: Transaction) => Buffer

validate

Takes a CBOR encoded input, validates it according to CIP-0021 and returns an array of found validation errors. The validation errors are of type ValidationError and we distinguish between fixable and unfixable errors. If the validate function reports:

• no fixable and no unfixable errors then the CBOR is already fully compliant with CIP-0021.
• only fixable errors then a call to a transform function will solve the found errors and the transaction will be compliant with CIP-0021.
• unfixable errors then the library is not able to transform the CBOR by itself.

Available methods:

validateTxBody(txBodyCbor: Buffer) => ValidationError[]
validateTx(txCbor: Buffer) => ValidationError[]

The list of all possible validation errors can be found here

transform

Takes a TransactionBody or Transaction object and applies non-destructive transformations on it to fix fixable validation errors. Returns a new transformed object of the same type. Available methods:

transformTxBody(txBody: TransactionBody) => TransactionBody
transformTx(tx: Transaction) => Transaction

Note: the length of the resulting CBOR might be increased or decreased which might affect the minimum required fee. An increase in CBOR length should be very rare.