when<TResult extends Object?> method

  1. @optionalTypeArgs
TResult when<TResult extends Object?>({
  1. required TResult success(
    1. T item,
    2. RequestDetails details
    ),
  2. required TResult failure(
    1. FailureReason reason,
    2. String message
    ),
})

A switch-like method, using callbacks.

As opposed to map, this offers destructuring. It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case Subclass2(:final field2):
    return ...;
}

Implementation

@optionalTypeArgs TResult when<TResult extends Object?>({required TResult Function( T item,  RequestDetails details)  success,required TResult Function( FailureReason reason,  String message)  failure,}) {final _that = this;
switch (_that) {
case WriteSuccess():
return success(_that.item,_that.details);case WriteFailure():
return failure(_that.reason,_that.message);}
}