skip building web previewer on osx.

azure-pipelines.yml

@@ -81,7 +81,7 @@ jobs:
         export PATH="$PATH:$HOME/.dotnet/tools"
         dotnet --info
         printenv
-        nuke --target CiAzureOSX --configuration Release
+        nuke --target CiAzureOSX --configuration Release --skip-previewer
 
   - task: PublishTestResults@2
     inputs:

nukebuild/Build.cs

@@ -126,12 +126,12 @@ partial class Build : NukeBuild
 
     Target CompileHtmlPreviewer => _ => _
         .DependsOn(Clean)
+        .OnlyWhenStatic(() => !Parameters.SkipPreviewer)
         .Executes(() =>
         {
             var webappDir = RootDirectory / "src" / "Avalonia.DesignerSupport" / "Remote" / "HtmlTransport" / "webapp";
 
             NpmTasks.NpmInstall(c => c
-                .AddPackages("typescript")
                 .SetWorkingDirectory(webappDir)
                 .SetArgumentConfigurator(a => a.Add("--silent")));
             NpmTasks.NpmRun(c => c

nukebuild/BuildParameters.cs

@@ -19,10 +19,14 @@ public partial class Build
     [Parameter("force-nuget-version")]
     public string ForceNugetVersion { get; set; }
 
+    [Parameter("skip-previewer")]
+    public bool SkipPreviewer { get; set; }
+
     public class BuildParameters
     {
         public string Configuration { get; }
         public bool SkipTests { get; }
+        public bool SkipPreviewer {get;}
         public string MainRepo { get; }
         public string MasterBranch { get; }
         public string RepositoryName { get; }
@@ -63,6 +67,7 @@ public partial class Build
             // ARGUMENTS
             Configuration = b.Configuration ?? "Release";
             SkipTests = b.SkipTests;
+            SkipPreviewer = b.SkipPreviewer;
 
             // CONFIGURATION
             MainRepo = "https://github.com/AvaloniaUI/Avalonia";