getTransactions function Null safety

Future<TransactionsResponse> getTransactions(
  1. String address,
  2. int page,
  3. String endpoint
)

Implementation

Future<TransactionsResponse> getTransactions(
    String address, int page, String endpoint) async {
  final Completer<TransactionsResponse> _completer =
      Completer<TransactionsResponse>();
  TransactionsResponse? transactionsResponse = TransactionsResponse();

  final Map<String, String> requestHeaders = {
    'Content-type': 'application/json',
    'Accept': 'application/json',
  };

  final String _body =
      '{"query":"query { transactionChain(address: \\"$address\\", page: $page) {address, type, data { ledger { uco { transfers { amount, to } }, nft { transfers { amount, to, nft } } } } } }"}';
  print(_body);

  try {
    final http.Response responseHttp = await http.post(
        Uri.parse(endpoint + '/api'),
        body: _body,
        headers: requestHeaders);
    print(responseHttp.body);

    if (responseHttp.statusCode == 200) {
      transactionsResponse = transactionsResponseFromJson(responseHttp.body);
    }
  } catch (e) {
    print('error: ' + e.toString());
  }

  _completer.complete(transactionsResponse);
  return _completer.future;
}