whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>({ TResult? bytes(double value)?, TResult? kb(double value)?, TResult? mb(double value)?, TResult? gb(double value)?, TResult? tb(double value)?, })

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 value)? bytes,
  TResult? Function(double value)? kb,
  TResult? Function(double value)? mb,
  TResult? Function(double value)? gb,
  TResult? Function(double value)? tb,
}) {
  final _that = this;
  switch (_that) {
    case BytesModel() when bytes != null:
      return bytes(_that.value);
    case KbModel() when kb != null:
      return kb(_that.value);
    case MbModel() when mb != null:
      return mb(_that.value);
    case GbModel() when gb != null:
      return gb(_that.value);
    case TbModel() when tb != null:
      return tb(_that.value);
    case _:
      return null;
  }
}