getMessageForSign method

String getMessageForSign({ required Map<String, dynamic> typedData, bool hash = true, bool include0x = true, })

Get a signable message from the typed data, accepts typedData and hash and hash is used when you want the hashed result of the output (keccak hash which ethereum uses)

Implementation

String getMessageForSign({
  required Map<String, dynamic> typedData,
  bool hash = true,
  bool include0x = true,
}) {
  Uint8List _primaryTypeHash = Uint8List.fromList([]);
  // MARK: step1. sanitize data
  final sanitizedData = sanitizeData(typedData);
  // MARK: step2. get struct hash of typedData with type EIP712Domain
  final _eip712DomainHash = hashStruct(
    'EIP712Domain',
    sanitizedData['domain'],
    sanitizedData['types'],
  );
  // MARK: step3. get struct hash of typedData with type primaryType

  if (sanitizedData['primaryType'] != 'EIP712Domain') {
    _primaryTypeHash = hashStruct(
      sanitizedData["primaryType"],
      sanitizedData['message'],
      sanitizedData['types'],
    );
  }
  // MARK: step4. concat `EIP_191_PREFIX` and first and second step to get the message
  final message = Uint8List.fromList([
    ...EIP_191_PREFIX,
    ..._eip712DomainHash,
    ..._primaryTypeHash,
  ]);
  if (hash) {
    final _res = HEX.encode(sha3_256(message));
    return include0x ? "0x$_res" : _res;
  }
  final _res = HEX.encode(message);
  return include0x ? "0x$_res" : _res;
}