update Author TH (#12394)

* update Author TH

* update Author TH

* update Author TH

* update Author TH

* update Author TH

* Update aspnetcore/mvc/views/tag-helpers/authoring.md

Co-Authored-By: reZach <reZach@users.noreply.github.com>

* Update aspnetcore/mvc/views/tag-helpers/authoring.md

Co-Authored-By: Luke Latham <1622880+guardrex@users.noreply.github.com>

* Update authoring.md

aspnetcore/mvc/views/tag-helpers/authoring.md

@@ -307,3 +307,12 @@ The tag helpers provide several properties to retrieve content.
 [!code-csharp[](../../views/tag-helpers/authoring/sample/AuthoringTagHelpers/src/AuthoringTagHelpers/TagHelpers/z1AutoLinkerCopy.cs?highlight=5,6,10&range=8-21)]
 
 * Multiple calls to `GetChildContentAsync` returns the same value and doesn't re-execute the `TagHelper` body unless you pass in a false parameter indicating not to use the cached result.
+
+## Load minified partial view TagHelper
+
+In production environments, performance can be improved by loading minified partial views. To take advantage of minified partial view in production:
+
+* Create/set up a pre-build process that minifies partial views.
+* Use the following code to load  minified partial views in non-development environments.
+
+[!code-csharp[](authoring/sample/AuthoringTagHelpers/src/MinifiedVersionTagHelper.cs?name=snippet)]

aspnetcore/mvc/views/tag-helpers/authoring/sample/AuthoringTagHelpers/src/MinifiedVersionTagHelper.cs

@@ -0,0 +1,44 @@
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.TagHelpers;
+using Microsoft.AspNetCore.Mvc.ViewEngines;
+using Microsoft.AspNetCore.Mvc.ViewFeatures.Internal;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+using System;
+using System.Threading.Tasks;
+
+namespace AuthoringTagHelpers.TagHelpers
+{
+    /// <summary>
+    ///     The minified-partial tag helper loads
+    ///     minified partials depending on the value
+    ///     of ASPNETCORE_ENVIRONMENT.
+    /// </summary>
+    #region snippet
+    public class MinifiedVersionPartialTagHelper : PartialTagHelper
+        {
+            public MinifiedVersionPartialTagHelper(ICompositeViewEngine viewEngine, 
+                                    IViewBufferScope viewBufferScope)
+                                   : base(viewEngine, viewBufferScope)
+            {
+
+            }
+
+            public override Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
+            {
+                // Append ".min" to load the minified partial view.
+                if (!IsDevelopment())
+                {
+                    Name += ".min";
+                }
+
+                return base.ProcessAsync(context, output);
+            }
+
+            private bool IsDevelopment()
+            {
+                return Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") 
+                                                     == EnvironmentName.Development;
+            }
+        }
+    #endregion
+}