TedToolkit.Results.Composition 2026.8.4

TedToolkit.Results.Composition

TedToolkit.Results.Composition adds optional branch-consumption and synchronous, Task, and collection composition extensions to the dependency-light TedToolkit.Results contract package.

Install

dotnet add package TedToolkit.Results.Composition

The extensions use the core TedToolkit.Results namespace, so the same import enables branch-safe consumption, deconstruction, and fluent pipelines:

using TedToolkit.Results;

var result = Result.Succeed<string, SaveFailure>("document.json");
var message = result.Match(
    value => $"Saved {value}",
    failure => $"Failed: {failure}");

var branch = result switch
{
    (true, var value, _) => value,
    (false, _, var failure) => failure.ToString(),
};

var path = result
    .Ensure(value => value.Length > 0, SaveFailure.InvalidDocument)
    .Map(value => value.ToUpperInvariant())
    .Recover(_ => "fallback.json");

enum SaveFailure
{
    InvalidDocument,
}

The inactive deconstructed payload is default; always use the Boolean discriminator.

Task composition uses the same fluent surface:

using TedToolkit.Results;

Result<Document, SaveFailure> loaded = await LoadAsync().ConfigureAwait(false);
Result<string, SaveFailure> path = await loaded
    .MapAsync((document, cancellationToken) => SaveAsync(document, cancellationToken))
    .ConfigureAwait(false);

Collection composition is ordered and fail-fast:

Result<IReadOnlyList<Document>, SaveFailure> documents = results.Sequence();

Sequence, Traverse, and Combine stop at the first failure. Task callbacks run only for the active branch, receive the supplied cancellation token, and propagate exceptions and cancellation.

Migration From Core Instance Methods

Installing this package preserves ordinary fluent calls such as result.Map(value => value.Length). C# does not support partially explicit generic arguments on extension methods. A call such as result.Map<int>(null!) must instead provide a typed delegate, for example:

result.Map((Func<string, int>)null!);

Removing the former core instance members is also a binary breaking change; existing consumers must reference Composition and recompile.

Target Frameworks

• net6.0
• net7.0
• net8.0
• net9.0
• net10.0
• net472
• net48
• netstandard2.0
• netstandard2.1

License

Licensed under LGPL-3.0.