fromNullableWith<L, R> function

Either<L, R> Function(R? value) fromNullableWith<L, R>(
  1. Lazy<L> orElse
)

A fromNullable variant that enforces the left and right types. Useful for function composition.

final transform = fromNullableWith<String, int>(() => 'number was missing')
  .compose(map((i) => i * 2));

expect(transform(1), right(2));
expect(transform(null), left('number was missing'));

Implementation

Either<L, R> Function(R? value) fromNullableWith<L, R>(
  Lazy<L> orElse,
) =>
    (value) => fromNullable(value, orElse);