How to transform .json files in Rider - transform

Question

In order to have different configurations available for testing of different mobile OS's, I'm trying to create transform files in Rider on (config/appsettings).json files.
On the rider website there's a blog showing how to do exactly that for .config files:
XDT configuration transformations in Rider
Visual Studio has an extension which allows .json transformations called SlowCheetah: SlowCheetah - Visual Studio Marketplace
So far I haven't been able to do this in Rider on .json files.

Answer 1

XDT stands for XML Data Transform, therefore JSON is not supported.
But you can use different JSON files per environment, as stated in the official docs:
// appsettings.json
{
"MyKey": "My default Value",
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
}
}
// appsettings.Development.json
{
"MyKey": "My Development Value"
}
// appsettings.Production.json
{
"MyKey": "My Production Value"
}
Please note that this is bound to the new .NET (aka .NET Core, .NET ≥ 5).

Answer 2

Ok, a heads up on my own question ;)
I figured I can alter the .csproj project file to create (but not generate) transform files:
<ItemGroup>
<None Update="Config\Config.Android.json">
<IsTransformFile>true</IsTransformFile>
<DependentUpon>Config.json</DependentUpon>
</None>
<None Update="Config\Config.IOS.json">
<IsTransformFile>true</IsTransformFile>
<DependentUpon>Config.json</DependentUpon>
</None>
<None Update="Config\Config.json">
<TransformOnBuild>true</TransformOnBuild>
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</None>
</ItemGroup>
<ItemGroup>
<None Update="appsettings.json">
<TransformOnBuild>true</TransformOnBuild>
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</None>
<None Update="appsettings.IOS.json">
<IsTransformFile>true</IsTransformFile>
<DependentUpon>appsettings.json</DependentUpon>
</None>
<None Update="appsettings.Android.json">
<IsTransformFile>true</IsTransformFile>
<DependentUpon>appsettings.json</DependentUpon>
</None>
</ItemGroup>