whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? formData(
    1. Map<String, String>? headers
    )?,
  2. TResult? basic(
    1. Map<String, String>? headers
    )?,
  3. TResult? data(
    1. Map<String, String>? headers
    )?,
})

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( Map<String, String>? headers)?  formData,TResult? Function( Map<String, String>? headers)?  basic,TResult? Function( Map<String, String>? headers)?  data,}) {final _that = this;
switch (_that) {
case _FormData() when formData != null:
return formData(_that.headers);case _Basic() when basic != null:
return basic(_that.headers);case _Data() when data != null:
return data(_that.headers);case _:
  return null;

}
}