Introduce async variant of Option.Map (#45)

* upgrade target framework

* introduce async option for map

* upgrade workflow to use .net 8

.github/workflows/dotnet-core.yml

@@ -15,7 +15,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 7.0.*
+        dotnet-version: 8.0.*
     - name: Install dependencies
       run: dotnet restore
     - name: Build

Galaxus.Functional.NUnit.Test/Galaxus.Functional.NUnit.Test.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFramework>net8.0</TargetFramework>
         <IsPackable>false</IsPackable>
     </PropertyGroup>
 

Galaxus.Functional.Tests/Galaxus.Functional.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFramework>net8.0</TargetFramework>
         <IsPackable>false</IsPackable>
     </PropertyGroup>
 

Galaxus.Functional.Tests/Option/Async/AsyncOptionExtensions.MapTest.cs

@@ -0,0 +1,45 @@
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace Galaxus.Functional.Tests.Option.Async;
+
+[TestFixture]
+internal class AsyncOptionExtensions_MapTest
+{
+    public sealed class MapAsyncTest
+    {
+        [Test]
+        public async Task TestMapAsync_WhenSelfIsSome()
+        {
+            var mapInvoked = false;
+
+            var subject = "value".ToOption();
+            var value = await subject.MapAsync(
+                s => Task.Run(() =>
+                {
+                    mapInvoked = true;
+                    return s.Length.ToOption();
+                }));
+
+            Assert.AreEqual(5.ToOption(), value);
+            Assert.IsTrue(mapInvoked);
+        }
+
+        [Test]
+        public async Task TestMapAsync_WhenSelfIsNone()
+        {
+            var mapInvoked = false;
+
+            var subject = Option<string>.None;
+            var value = await subject.MapAsync(
+                s => Task.Run(() =>
+                {
+                    mapInvoked = true;
+                    return s.Length.ToOption();
+                }));
+
+            Assert.AreEqual(Option<int>.None, value);
+            Assert.IsFalse(mapInvoked);
+        }
+    }
+}

Galaxus.Functional/(Option)/(Async)/AsyncOptionExtensions.Map.cs

@@ -73,4 +73,8 @@ public static async Task<TTo> MapOrElseAsync<T, TTo>(this Option<T> self, Func<T
     {
         return await self.MapOrElse(map, fallback).ConfigureAwait(false);
     }
+
+    /// <inheritdoc cref="Option{T}.Map{TTo}"/>
+    public static Task<Option<TTo>> MapAsync<T, TTo>(this Option<T> self, Func<T, Task<Option<TTo>>> map)
+        => self.MapOrElseAsync(map, () => Option<TTo>.None);
 }