whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? string(
    1. String labelBuilder(
      1. T data
      ),
    2. ListDataTileStyle? style
    )?,
  2. TResult? custom(
    1. Widget builder(
      1. BuildContext context,
      2. T data,
      3. ListTileMetadata metadata
      )
    )?,
})

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 Function(T data) labelBuilder,  ListDataTileStyle? style)?  string,TResult? Function( Widget Function(BuildContext context, T data, ListTileMetadata metadata) builder)?  custom,}) {final _that = this;
switch (_that) {
case ListDataBuilderString() when string != null:
return string(_that.labelBuilder,_that.style);case ListDataBuilderCustom() when custom != null:
return custom(_that.builder);case _:
  return null;

}
}