Result<L, R>.fromNullable constructor

Result<L, R>.fromNullable(
  1. R? value,
  2. L onNull()
)

Creates a Success from a non-null value, or Failure from onNull if null.

Useful for bridging nullable APIs into the Result world.

final result = Result<String, int>.fromNullable(
  json['age'] as int?,
  () => 'age field is missing',
); // Success(25) or Failure('age field is missing')

Implementation

factory Result.fromNullable(R? value, L Function() onNull) =>
    value != null ? Success<L, R>(value) : Failure<L, R>(onNull());