whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? getItem(
    1. String operationId,
    2. String itemId,
    3. @RequestDetailsConverter() RequestDetails details,
    4. DateTime createdAt,
    5. int attemptNumber,
    )?,
  2. TResult? getItems(
    1. String operationId,
    2. @RequestDetailsConverter() RequestDetails details,
    3. DateTime createdAt,
    4. int attemptNumber,
    )?,
  3. TResult? getByIds(
    1. String operationId,
    2. Set<String> itemIds,
    3. @RequestDetailsConverter() RequestDetails details,
    4. DateTime createdAt,
    5. int attemptNumber,
    )?,
  4. TResult? setItem(
    1. String operationId,
    2. @RequestDetailsConverter() RequestDetails details,
    3. T item,
    4. DateTime createdAt,
    5. int attemptNumber,
    )?,
  5. TResult? setItems(
    1. String operationId,
    2. @RequestDetailsConverter() RequestDetails details,
    3. Iterable<T> items,
    4. DateTime createdAt,
    5. int attemptNumber,
    )?,
  6. TResult? delete(
    1. String operationId,
    2. String itemId,
    3. @RequestDetailsConverter() RequestDetails details,
    4. DateTime createdAt,
    5. int attemptNumber,
    )?,
})

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( String operationId,  String itemId, @RequestDetailsConverter()  RequestDetails details,  DateTime createdAt,  int attemptNumber)?  getItem,TResult? Function( String operationId, @RequestDetailsConverter()  RequestDetails details,  DateTime createdAt,  int attemptNumber)?  getItems,TResult? Function( String operationId,  Set<String> itemIds, @RequestDetailsConverter()  RequestDetails details,  DateTime createdAt,  int attemptNumber)?  getByIds,TResult? Function( String operationId, @RequestDetailsConverter()  RequestDetails details,  T item,  DateTime createdAt,  int attemptNumber)?  setItem,TResult? Function( String operationId, @RequestDetailsConverter()  RequestDetails details,  Iterable<T> items,  DateTime createdAt,  int attemptNumber)?  setItems,TResult? Function( String operationId,  String itemId, @RequestDetailsConverter()  RequestDetails details,  DateTime createdAt,  int attemptNumber)?  delete,}) {final _that = this;
switch (_that) {
case ReadOperation() when getItem != null:
return getItem(_that.operationId,_that.itemId,_that.details,_that.createdAt,_that.attemptNumber);case ReadListOperation() when getItems != null:
return getItems(_that.operationId,_that.details,_that.createdAt,_that.attemptNumber);case ReadByIdsOperation() when getByIds != null:
return getByIds(_that.operationId,_that.itemIds,_that.details,_that.createdAt,_that.attemptNumber);case WriteOperation() when setItem != null:
return setItem(_that.operationId,_that.details,_that.item,_that.createdAt,_that.attemptNumber);case WriteListOperation() when setItems != null:
return setItems(_that.operationId,_that.details,_that.items,_that.createdAt,_that.attemptNumber);case DeleteOperation() when delete != null:
return delete(_that.operationId,_that.itemId,_that.details,_that.createdAt,_that.attemptNumber);case _:
  return null;

}
}