whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(double amount, String currency, String merchantTransactionId, int mid, String paymentMode, String productType, String terminalId, String transactionDate, String? txnNote, String txnType, int udf1, String udf2, String udf3, String udf4, String udf5, String udf6, String udf7, String udf8, String udf9, String udf10, String callbackUrl, String ru,)?)

A variant of when that fallback to returning null

It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case _:
    return null;
}

Implementation

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? Function( double amount,  String currency,  String merchantTransactionId,  int mid,  String paymentMode,  String productType,  String terminalId,  String transactionDate,  String? txnNote,  String txnType,  int udf1,  String udf2,  String udf3,  String udf4,  String udf5,  String udf6,  String udf7,  String udf8,  String udf9,  String udf10,  String callbackUrl,  String ru)?  $default,) {final _that = this;
switch (_that) {
case _PgRequest() when $default != null:
return $default(_that.amount,_that.currency,_that.merchantTransactionId,_that.mid,_that.paymentMode,_that.productType,_that.terminalId,_that.transactionDate,_that.txnNote,_that.txnType,_that.udf1,_that.udf2,_that.udf3,_that.udf4,_that.udf5,_that.udf6,_that.udf7,_that.udf8,_that.udf9,_that.udf10,_that.callbackUrl,_that.ru);case _:
  return null;

}
}