FailOr.Validations 1.1.0

FailOr.Validations

FailOr.Validations is the typed companion package for property-based validation on plain T values. It builds on top of FailOr and adds selector-driven validation and validation-plus-transform helpers.

Install

dotnet add package FailOr.Validations

FailOr.Validations depends on FailOr, so the core package is restored automatically.

Behavior

• Validate(...) and ValidateAsync(...) run one or more property-based validators and return the original input instance on success.
• ValidateThenTransform(...) and ValidateThenTransformAsync(...) run one or more property-based mappers and invoke the final transform only when every mapper succeeds.
• Only Failures.Validation instances are rewritten to the selected leaf property name such as Name or City.
• Failures.General and Failures.Exceptional are preserved unchanged.
• Async validators and async mappers run sequentially and preserve declaration order.

Quick Start

Validate and keep the original value:

using FailOr;
using FailOr.Validation;

var person = new Person
{
    Name = "Ada",
    Nickname = "Ace",
    Address = new Address { City = "Boston" }
};

var result = person.Validate(
    (x => x.Name, name => string.IsNullOrWhiteSpace(name)
        ? FailOr.Fail<int>(Failure.Validation("Ignored", "Name is required."))
        : FailOr.Success(1)),
    (x => x.Address.City, city => string.IsNullOrWhiteSpace(city)
        ? FailOr.Fail<int>(Failure.Validation("Ignored", "City is required."))
        : FailOr.Success(1)));

Map selected properties and transform the mapped values:

using FailOr;
using FailOr.Validation;

var result = person.ValidateThenTransform(
    (x => x.Name, name => string.IsNullOrWhiteSpace(name)
        ? FailOr.Fail<string>(Failure.Validation("Ignored", "Name is required."))
        : FailOr.Success(name.ToUpperInvariant())),
    (x => x.Address.City, city => string.IsNullOrWhiteSpace(city)
        ? FailOr.Fail<string>(Failure.Validation("Ignored", "City is required."))
        : FailOr.Success(city.ToUpperInvariant())),
    (name, city) => $"{name}|{city}");

Run async validators and async transforms:

using FailOr;
using FailOr.Validation;

var result = await person.ValidateThenTransformAsync(
    (x => x.Name, async name =>
    {
        await Task.Delay(1);
        return string.IsNullOrWhiteSpace(name)
            ? FailOr.Fail<string>(Failure.Validation("Ignored", "Name is required."))
            : FailOr.Success(name.ToUpperInvariant());
    }),
    async name =>
    {
        await Task.Delay(1);
        return $"Hello {name}";
    });

Documentation

• Repository overview: FailOr root README
• Core package readme: src/FailOr/README.md
• Validations API reference: docs/validations-api-reference.md

License

Licensed under the MIT License. See LICENSE.