when<TResult extends Object?> method

  1. @optionalTypeArgs
TResult when<TResult extends Object?>(
  1. TResult $default(
    1. PPAmount? handlingFee,
    2. PPAmount? insurance,
    3. PPAmount? shippingAndHandling,
    4. PPAmount? shippingDiscount,
    5. PPAmount? subtotal,
    6. PPAmount? tax,
    7. PPAmount? total,
    )
)

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?>(
  TResult Function(
          PPAmount? handlingFee,
          PPAmount? insurance,
          PPAmount? shippingAndHandling,
          PPAmount? shippingDiscount,
          PPAmount? subtotal,
          PPAmount? tax,
          PPAmount? total)
      $default,
) {
  final _that = this;
  switch (_that) {
    case _CartAmounts():
      return $default(
          _that.handlingFee,
          _that.insurance,
          _that.shippingAndHandling,
          _that.shippingDiscount,
          _that.subtotal,
          _that.tax,
          _that.total);
    case _:
      throw StateError('Unexpected subclass');
  }
}