Infrastructure.Option 8.8.0

Usage

Get the NuGet package here: Infrastructure.Option on NuGet

Overview

Option<T> is a simple option type usable in C#.

• Option.Some<T> represents an available value.
• Option.None<T> represents the absence of a value.

The Option static class provides factory methods to create instances of Option<T>.

For more information about option types, see Option type on Wikipedia.

Basic manipulation of Option is done via the Choose() and Otherwise() functions.

• Choose() selects the underlying values, i.e., those of type Some<T>.
• Otherwise() defines fallback behavior when encountering None<T>.

Examples

Creating Some values

var someString = Option.Some("Example value");
var someInteger = Option.Some(12345);

Creating None values

var noneString = Option.None<string>();
var noneInteger = Option.None<int>();

Pattern matching optional values

var option = Option.Some("Example value");
var value = option is Some<string> some ? some.Value : "Something else";

Fallback values using fluent syntax

var option = Option.None<string>();
var optionalFallbackValue = Option.Some("Example value");
var fallbackValue = Option.Some("Example value");

var fallbackToOptionalValue = option.Otherwise(optionalFallbackValue);
var fallbackToValue = option.Otherwise(fallbackValue);

var fallbackToOptionalValueProvidedByFactory = option.Otherwise(() => optionalFallbackValue);
var fallbackToValueProvidedByFactory = option.Otherwise(() => fallbackValue);

Choosing the first value from multiple options

var options = new[] {
    Option.None<string>(),
    Option.Some("Example value")
};

var option = options.ChooseFirst();

Selecting existing values from a collection

var collection = new Option<string>[] {
    Option.None<string>(),
    Option.Some("1"),
    Option.None<string>(),
    Option.Some("2"),
    Option.None<string>(),
    Option.Some("3"),
    Option.None<string>(),
};

var values = collection.Choose(); // returns [ "1", "2", "3" ]

Selecting values with mapping

record ExampleType(string ExampleProperty);

var collection = new[] {
    Option.None<ExampleType>(),
    Option.Some(new ExampleType("1")),
    Option.None<ExampleType>(),
    Option.Some(new ExampleType("2")),
    Option.None<ExampleType>(),
    Option.Some(new ExampleType("3")),
    Option.None<ExampleType>(),
};

var propertyValues = collection.Choose(entry => entry.ExampleProperty); // returns [ "1", "2", "3" ]

Checking if value matches the given predicate

var option = Option.Some("Example value");

var holds = option.Holds(example => example == "Example value"); // holds == true

JSON Serialization

Infrastructure.Option supports JSON serialization using System.Text.Json without requiring any additional dependencies.

The Option<T> type is serialized as an object with a single ValueOrNull property that contains the wrapped value.

This approach produces idiomatic JSON for both .NET and the broader JSON ecosystem, and the optional value is clearly described in OpenAPI documentation.

For example, Option.Some("Hello!") is serialized as:

{ "ValueOrNull": "Hello!" }