fold<R> method

R fold<R>(
  1. R onOk(
    1. T value
    ),
  2. R onErr(
    1. E error
    )
)

Collapses the result with onOk or onErr, producing a single value of type R.

result.fold(
  (user) => 'User: $user',
  (err)  => 'Error: $err',
);

Implementation

R fold<R>(R Function(T value) onOk, R Function(E error) onErr) {
  if (isOk) return onOk((this as Ok<T, E>).value);
  return onErr((this as Err<T, E>).error);
}