result_monad 4.0.0

A Dart implementation of the Result Monad which allows for more expressive result generation and processing without using exceptions.

4.0.0

• Change Ok class's field to be "value" which overrides base-class value property. Since the 3.x version has been pulled and this technically changes the field of Ok, even though it wouldn't normally be used. This technically bumps the version number to 4.0.0

3.0.2

• Fix having version in CHANGELOG align with pub.dev version to get perfect score.

3.0.1

• Update README to new syntax

3.0.0

NOTE 1: This release has some breaking changes and an increased minimum SDK version bump from the 2.3.2 release.

NOTE 2: Many thanks to the contributions to the ADT-related updates and StackTrace functionality updates contributed by Daniel Gomez Rico ([e-mail]). Some of the changes were taken through Pull Request acceptance while others were back-ported with some changes from his fork of this project

• Underlying architecture now uses Algebraic Data Type (ADT) functionality introduced with class modifiers and patterns in Dart 3.0.0 in May 2023.
  • This made the syntax for creating Results more compact (and preferred way to create Results now):
    • Result.ok('Good') => Ok('Good)
    • Result.error('Bad') => Error('Bad')
  • This also makes it so you can use switch statements, if statements, et cetera on return values directly, although somewhat redudant with the various aggregation operations in the library.
  • Example:

// The below fold function...
final value = invert(2).fold(
  onSuccess: (v) => v,
  onError: (e, trace) => e,
);

// Can be expressed:
final value = switch (invert(2)) {
  Ok o => o.value,
  Error e => e.cause,
  Result _ => throw UnimplementedError(), // there since Result isn't sealed
};

• Breaking change: Minimum Dart version bumped up from 2.14.4 to 3.0.0
• Breaking change: Added Stack Trace following functionality so can get insight into where the error occurred in a chain of calls. This changed the function signatures on the following method to add access to stack traces when processing errors
  • On Result: fold, match, withError, withErrorAsync
  • On FutureResult: fold, match, withError, withErrorAsync
• Add optional StackTrace parameter on Error result creation Error('Bad', StackTrace.current)
• Result has a stackTrace property that can be called if and only if the type is an Error. Result can be null.
• Result has asOk and asError properties for casting to specific type. This will throw an Exception if is against the underlying type for that instance.
• Thanks to GitLab User DoodleSchrank for adding additional pass-through methods on FutureResult to their corresponding Result methods: getErrorOrElse, getValueOrElse, getErrorOrElseAsync, getValueOrElseAsync
• Updated examples and documentation to reflect the syntax updates.

2.3.2

• Tweak to documentation headers to avoid lint error

2.3.1

• Tweak to README to include withError and withErrorAsync

2.3.0

• Examples and documentation updates for the new syntax.
• Add to FutureResult: andThen, errorCast, mapError, mapValue, withResult, withError, match, fold
• Add withError to Result and withError and withErrorAsync to FutureResult

2.1.0

• Add pass through methods withResult and withResultAsync on Result and Future extension method

2.0.2

• Add exception catching on addThen and addThenSuccess and FutureResult extension methods.

2.0.1

• Tweaks to the README only.

2.0.0

• Allow nullable types for success and failure types
• Add andThenSuccess and andThenSuccessAsync methods for allowing returning results without explicit Result.ok wrapping to allow more concise syntax
• Add extension methods on FutureResult to make async chaining syntax much more concise
• Add errorCast method for when need to pass up an error Result with the same error type with different success type.

1.0.2

• Tweaks to API documentation
• Added temp file "intermediate" level example and added it to example.md as well

1.0.1

• Added an example.md file for pub.dev.

1.0.0

• Initial version.