Nerdigy.Results

A lightweight Result and Error type for .NET applications. Provides a simple, functional approach to error handling without exceptions.

Installation

dotnet add package Nerdigy.Results

Usage

Basic Result (no value)

Result result = Result.Success;
Result failure = Result.Failure(new NotFoundError("User not found"));

// Implicit conversion from Error
Result implicit = new BadRequestError("Invalid input");

Result with a value

Result<int> result = Result<int>.Success(42);
Result<int> failure = Result<int>.Failure(new InternalError());

// Implicit conversions
Result<int> fromValue = 42;
Result<int> fromError = new NotFoundError("Not found");

Checking outcomes

if (result.IsSuccess)
{
    Console.WriteLine(result.Value);
}

if (result.IsFailure)
{
    Console.WriteLine(result.Error);
}

Match

var message = result.Match(
    onSuccess: value => $"Got {value}",
    onFailure: error => $"Failed: {error}"
);

Map

Result<string> mapped = result.Map(value => value.ToString());

Bind

Result<string> bound = result.Bind(value => Result<string>.Success(value.ToString()));

Tap

result.Tap(value => Console.WriteLine($"Side effect: {value}"));

Async variants

All core operations have async counterparts: MatchAsync, MapAsync, BindAsync, and TapAsync.

var message = await result.MatchAsync(
    onSuccess: async value => await FormatAsync(value),
    onFailure: async error => await LogErrorAsync(error)
);

Error Types

The library includes a set of built-in error types that map to common HTTP status codes:

Error Type	HTTP Status
BadRequestError	400
ValidationError	400
UnauthorizedError	401
ForbiddenError	403
NotFoundError	404
ConflictError	409
UnprocessableError	422
TooManyRequestsError	429
InternalError	500
ServiceUnavailableError	503
GatewayTimeoutError	504

All error types are records that extend the base Error record, so you can create custom errors by extending Error as well.

License

MIT