From e1b1f8f6fc354374eb9c5349607e1c7437e2cc69 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 26 Mar 2025 18:50:24 +0100
Subject: [PATCH 01/18] Rewrite placeholder in HTML

---
 .../Tasks/WriteImportMapToHtml.cs             | 91 ++++++++++++++++---
 1 file changed, 79 insertions(+), 12 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index a7478f89018c..08b63b1191f1 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -46,6 +46,8 @@ public partial class WriteImportMapToHtml : Task
 
     private static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
 
+    private static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""\s*[/]?>");
+
     public override bool Execute()
     {
         var endpoints = StaticWebAssetEndpoint.FromItemGroup(Endpoints).Where(e => e.AssetFile.EndsWith(".js") || e.AssetFile.EndsWith(".mjs"));
@@ -75,6 +77,13 @@ public override bool Execute()
                     return $"<script type=\"importmap\">{JsonSerializer.Serialize(importMap, ImportMapSerializerContext.CustomEncoder.Options)}</script>";
                 });
 
+                // Generate import map
+                outputContent = _preloadRegex.Replace(content, e =>
+                {
+                    Log.LogMessage("Writing preload links to '{0}'", item.ItemSpec);
+                    return GeneratePreloadLinks(resources);
+                });
+
                 // Fingerprint all assets used in html
                 outputContent = _assetsRegex.Replace(outputContent, e =>
                 {
@@ -105,6 +114,42 @@ public override bool Execute()
         return true;
     }
 
+    private static string GeneratePreloadLinks(List<ResourceAsset> assets)
+    {
+        var links = new List<(string? Order, string Value)>();
+        foreach (var asset in assets)
+        {
+            if (asset.PreloadRel == null)
+            {
+                continue;
+            }
+
+            string link = $"<link href=\"{asset.Url}\" rel=\"{asset.PreloadRel}\"";
+            if (!string.IsNullOrEmpty(asset.PreloadAs))
+            {
+                link = String.Concat(link, " as=\"", asset.PreloadAs, "\"");
+            }
+            if (!string.IsNullOrEmpty(asset.PreloadPriority))
+            {
+                link = String.Concat(link, " fetchpriority=\"", asset.PreloadPriority, "\"");
+            }
+            if (!string.IsNullOrEmpty(asset.PreloadCrossorigin))
+            {
+                link = String.Concat(link, " crossorigin=\"", asset.PreloadCrossorigin, "\"");
+            }
+            if (!string.IsNullOrEmpty(asset.Integrity))
+            {
+                link = String.Concat(link, " integrity=\"", asset.Integrity, "\"");
+            }
+
+            link += " />";
+            links.Add((asset.PreloadOrder, link));
+        }
+
+        links.Sort((a, b) => string.Compare(a.Order, b.Order, StringComparison.InvariantCulture));
+        return String.Join(Environment.NewLine, links);
+    }
+
     private string GetFingerprintedAssetPath(Dictionary<string, ResourceAsset> urlMappings, string assetPath)
     {
         if (urlMappings.TryGetValue(assetPath, out var asset) && (!IncludeOnlyHardFingerprintedModules || asset.IsHardFingerprinted))
@@ -125,33 +170,50 @@ internal List<ResourceAsset> CreateResourcesFromEndpoints(IEnumerable<StaticWebA
         // subresource integrity to things like images, script tags, etc.
         foreach (var endpoint in endpoints)
         {
-            string? label = null;
-            string? integrity = null;
-
             // If there's a selector this means that this is an alternative representation for a resource, so skip it.
             if (endpoint.Selectors?.Length == 0)
             {
+                var resourceAsset = new ResourceAsset(endpoint.Route);
                 for (var i = 0; i < endpoint.EndpointProperties?.Length; i++)
                 {
                     var property = endpoint.EndpointProperties[i];
                     if (property.Name.Equals("label", StringComparison.OrdinalIgnoreCase))
                     {
-                        label = property.Value;
+                        resourceAsset.Label = property.Value;
                     }
                     else if (property.Name.Equals("integrity", StringComparison.OrdinalIgnoreCase))
                     {
-                        integrity = property.Value;
+                        resourceAsset.Integrity = property.Value;
+                    }
+                    else if (property.Name.Equals("preloadrel", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadRel = property.Value;
+                    }
+                    else if (property.Name.Equals("preloadas", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadAs = property.Value;
+                    }
+                    else if (property.Name.Equals("preloadpriority", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadPriority = property.Value;
+                    }
+                    else if (property.Name.Equals("preloadcrossorigin", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadCrossorigin = property.Value;
+                    }
+                    else if (property.Name.Equals("preloadorder", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadOrder = property.Value;
                     }
                 }
 
-                bool isHardFingerprinted = true;
                 var asset = Assets.FirstOrDefault(a => a.ItemSpec == endpoint.AssetFile);
                 if (asset != null)
                 {
-                    isHardFingerprinted = asset.GetMetadata("RelativePath").Contains("#[.{fingerprint}]!");
+                    resourceAsset.IsHardFingerprinted = asset.GetMetadata("RelativePath").Contains("#[.{fingerprint}]!");
                 }
 
-                resources.Add(new ResourceAsset(endpoint.Route, label, integrity, isHardFingerprinted));
+                resources.Add(resourceAsset);
             }
         }
 
@@ -207,12 +269,17 @@ private static Dictionary<string, ResourceAsset> GroupResourcesByLabel(List<Reso
     }
 }
 
-internal sealed class ResourceAsset(string url, string? label, string? integrity, bool isHardFingerprinted)
+internal sealed class ResourceAsset(string url)
 {
     public string Url { get; } = url;
-    public string? Label { get; set; } = label;
-    public string? Integrity { get; set; } = integrity;
-    public bool IsHardFingerprinted { get; set; } = isHardFingerprinted;
+    public string? Label { get; set; }
+    public string? Integrity { get; set; }
+    public string? PreloadRel { get; set; }
+    public string? PreloadAs { get; set; }
+    public string? PreloadPriority { get; set; }
+    public string? PreloadCrossorigin { get; set; }
+    public string? PreloadOrder { get; set; }
+    public bool IsHardFingerprinted { get; set; } = true;
 }
 
 internal class ImportMap(Dictionary<string, string> imports, Dictionary<string, Dictionary<string, string>> scopes, Dictionary<string, string> integrity)

From c1fe23965db1c62338a67df3f949533648d2ef4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Thu, 27 Mar 2025 11:12:06 +0100
Subject: [PATCH 02/18] Use only value

---
 src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index 08b63b1191f1..df83b25f4460 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -147,7 +147,7 @@ private static string GeneratePreloadLinks(List<ResourceAsset> assets)
         }
 
         links.Sort((a, b) => string.Compare(a.Order, b.Order, StringComparison.InvariantCulture));
-        return String.Join(Environment.NewLine, links);
+        return String.Join(Environment.NewLine, links.Select(l => l.Value));
     }
 
     private string GetFingerprintedAssetPath(Dictionary<string, ResourceAsset> urlMappings, string assetPath)

From 1c883919ab82a4a1e7876f40e2af45eef41bf59a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Thu, 27 Mar 2025 15:37:53 +0100
Subject: [PATCH 03/18] Fix link element generation

---
 src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index df83b25f4460..a9c60d42b878 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -78,7 +78,7 @@ public override bool Execute()
                 });
 
                 // Generate import map
-                outputContent = _preloadRegex.Replace(content, e =>
+                outputContent = _preloadRegex.Replace(outputContent, e =>
                 {
                     Log.LogMessage("Writing preload links to '{0}'", item.ItemSpec);
                     return GeneratePreloadLinks(resources);

From 3c17f314a38b6ad9cb6d4eefb144881ff0b7f404 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Thu, 27 Mar 2025 15:38:21 +0100
Subject: [PATCH 04/18] Ordered DependsOn properties to allow to hook in

---
 ...NET.Sdk.StaticWebAssets.HtmlImportMap.targets | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
index 579338938557..17d976d6ef43 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
@@ -35,12 +35,12 @@ Copyright (c) .NET Foundation. All rights reserved.
       ResolveHtmlImportMapBuildStaticWebAssets
     </ResolveBuildServiceWorkerStaticWebAssetsDependsOn>
     <ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
-      GenerateHtmlImportMapBuildStaticWebAssets;
-      $(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn)
+      $(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn);
+      GenerateHtmlImportMapBuildStaticWebAssets
     </ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
     <GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
-      ResolveHtmlImportMapBuildConfiguration;
-      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)
+      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapBuildConfiguration
     </GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
 
     <!--
@@ -62,12 +62,12 @@ Copyright (c) .NET Foundation. All rights reserved.
       ResolveHtmlImportMapPublishStaticWebAssets
     </ResolvePublishServiceWorkerStaticWebAssetsDependsOn>
     <ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
-      GenerateHtmlImportMapPublishStaticWebAssets;
-      $(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn)
+      $(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn);
+      GenerateHtmlImportMapPublishStaticWebAssets
     </ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
     <GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
-      ResolveHtmlImportMapPublishConfiguration;
-      $(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn)
+      $(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn);
+      ResolveHtmlImportMapPublishConfiguration
     </GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
 
   </PropertyGroup>

From 4a88cef47a6aabab4c0df62917b29230188cc3fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Thu, 27 Mar 2025 15:38:45 +0100
Subject: [PATCH 05/18] Add test on VanillaWasm app

---
 .../StaticWebAssetsFingerprintingTest.cs      | 20 ++++---
 .../VanillaWasm/VanillaWasm.csproj            | 53 +++++++++++++++++++
 .../VanillaWasm/wwwroot/index.html            |  1 +
 3 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
index feb337d3c2c2..521b1021dd6f 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
@@ -57,38 +57,38 @@ public void Build_FingerprintsContent_WhenEnabled()
     [MemberData(nameof(WriteImportMapToHtmlData))]
     public void Build_WriteImportMapToHtml(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
     {
-        ProjectDirectory = CreateAspNetSdkTestAsset(testAsset);
+        ProjectDirectory = CreateAspNetSdkTestAsset(testAsset, identifier: $"{testAsset}_{fingerprintUserJavascriptAssets}_{expectFingerprintOnScript}");
         ReplaceStringInIndexHtml(ProjectDirectory, scriptPath, scriptPathWithFingerprintPattern);
         FingerprintUserJavascriptAssets(fingerprintUserJavascriptAssets);
 
         var build = CreateBuildCommand(ProjectDirectory);
-        ExecuteCommand(build, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets}").Should().Pass();
+        ExecuteCommand(build, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
 
         var intermediateOutputPath = build.GetIntermediateDirectory(DefaultTfm, "Debug").ToString();
         var indexHtmlPath = Directory.EnumerateFiles(Path.Combine(intermediateOutputPath, "staticwebassets", "importmaphtml", "build"), "*.html").Single();
         var endpointsManifestPath = Path.Combine(intermediateOutputPath, $"staticwebassets.build.endpoints.json");
 
-        AssertImportMapInHtml(indexHtmlPath, endpointsManifestPath, scriptPath, expectFingerprintOnScript: expectFingerprintOnScript);
+        AssertImportMapInHtml(indexHtmlPath, endpointsManifestPath, scriptPath, expectFingerprintOnScript: expectFingerprintOnScript, expectPreloadElement: testAsset == "VanillaWasm");
     }
 
     [Theory]
     [MemberData(nameof(WriteImportMapToHtmlData))]
     public void Publish_WriteImportMapToHtml(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
     {
-        ProjectDirectory = CreateAspNetSdkTestAsset(testAsset);
+        ProjectDirectory = CreateAspNetSdkTestAsset(testAsset, identifier: $"{testAsset}_{fingerprintUserJavascriptAssets}_{expectFingerprintOnScript}");
         ReplaceStringInIndexHtml(ProjectDirectory, scriptPath, scriptPathWithFingerprintPattern);
         FingerprintUserJavascriptAssets(fingerprintUserJavascriptAssets);
 
         var projectName = Path.GetFileNameWithoutExtension(Directory.EnumerateFiles(ProjectDirectory.TestRoot, "*.csproj").Single());
 
         var publish = CreatePublishCommand(ProjectDirectory);
-        ExecuteCommand(publish, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets}").Should().Pass();
+        ExecuteCommand(publish, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
 
         var outputPath = publish.GetOutputDirectory(DefaultTfm, "Debug").ToString();
         var indexHtmlOutputPath = Path.Combine(outputPath, "wwwroot", "index.html");
         var endpointsManifestPath = Path.Combine(outputPath, $"{projectName}.staticwebassets.endpoints.json");
 
-        AssertImportMapInHtml(indexHtmlOutputPath, endpointsManifestPath, scriptPath, expectFingerprintOnScript: expectFingerprintOnScript);
+        AssertImportMapInHtml(indexHtmlOutputPath, endpointsManifestPath, scriptPath, expectFingerprintOnScript: expectFingerprintOnScript, expectPreloadElement: testAsset == "VanillaWasm");
     }
 
     private void FingerprintUserJavascriptAssets(bool fingerprintUserJavascriptAssets)
@@ -125,7 +125,7 @@ private void ReplaceStringInIndexHtml(TestAsset testAsset, string sourceValue, s
         }
     }
 
-    private void AssertImportMapInHtml(string indexHtmlPath, string endpointsManifestPath, string scriptPath, bool expectFingerprintOnScript = true)
+    private void AssertImportMapInHtml(string indexHtmlPath, string endpointsManifestPath, string scriptPath, bool expectFingerprintOnScript = true, bool expectPreloadElement = false)
     {
         var indexHtmlContent = File.ReadAllText(indexHtmlPath);
         var endpoints = JsonSerializer.Deserialize<StaticWebAssetEndpointsManifest>(File.ReadAllText(endpointsManifestPath));
@@ -150,6 +150,12 @@ private void AssertImportMapInHtml(string indexHtmlPath, string endpointsManifes
         Assert.Contains(GetFingerprintedPath("_framework/dotnet.native.js"), indexHtmlContent);
         Assert.Contains(GetFingerprintedPath("_framework/dotnet.runtime.js"), indexHtmlContent);
 
+        if (expectPreloadElement)
+        {
+            Assert.DoesNotContain("<link rel=\"preload\">", indexHtmlContent);
+            Assert.Contains($"<link href=\"{fingerprintedScriptPath}\" rel=\"preload\" as=\"script\" fetchpriority=\"high\" crossorigin=\"anonymous\"", indexHtmlContent);
+        }
+
         string GetFingerprintedPath(string route)
             => endpoints.Endpoints.FirstOrDefault(e => e.Route == route && e.Selectors.Length == 0)?.AssetFile ?? throw new Exception($"Missing endpoint for file '{route}' in '{endpointsManifestPath}'");
     }
diff --git a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
index 9676d0bfc24d..f275acb37c94 100644
--- a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
+++ b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
@@ -2,5 +2,58 @@
   <PropertyGroup>
     <TargetFramework>$(CurrentTargetFramework)</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+      _AddAppPreloadProperties;
+      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)
+    </GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
   </PropertyGroup>
+  <Target Name="_AppConfigurePreload">
+    <ItemGroup>
+      <_AppendPreloadRelPreloadProperty Include="Append">
+        <UpdateTarget>Property</UpdateTarget>
+        <Name>PreloadRel</Name>
+        <Value>preload</Value>
+      </_AppendPreloadRelPreloadProperty>
+      <_AppendPreloadAsScriptProperty Include="Append">
+        <UpdateTarget>Property</UpdateTarget>
+        <Name>PreloadAs</Name>
+        <Value>script</Value>
+      </_AppendPreloadAsScriptProperty>
+      <_AppendPreloadPriorityHighProperty Include="Append">
+        <UpdateTarget>Property</UpdateTarget>
+        <Name>PreloadPriority</Name>
+        <Value>high</Value>
+      </_AppendPreloadPriorityHighProperty>
+      <_AppendPreloadCrossoriginAnonymousProperty Include="Append">
+        <UpdateTarget>Property</UpdateTarget>
+        <Name>PreloadCrossorigin</Name>
+        <Value>anonymous</Value>
+      </_AppendPreloadCrossoriginAnonymousProperty>
+    </ItemGroup>
+  </Target>
+  <Target Name="_AddAppPreloadProperties" DependsOnTargets="_AppConfigurePreload;_AddWasmStaticWebAssets" BeforeTargets="GenerateStaticWebAssetsManifest">
+    <ItemGroup>
+      <_AppPreloadScriptAsset Include="@(StaticWebAsset)" Condition="'%(FileName)%(Extension)' == 'main.js'" />
+      <_AppPreloadEndpointFilter Include="Property" Name="Label" Mode="Include" Condition="'$(FingerprintUserJavascriptAssets)' == 'true'" />
+      <_AppPreloadEndpointFilter Include="Property" Name="Label" Mode="Exclude" Condition="'@(_AppPreloadEndpointFilter)' == ''" />
+    </ItemGroup>
+    <FilterStaticWebAssetEndpoints
+      Endpoints="@(StaticWebAssetEndpoint)"
+      Assets="@(_AppPreloadScriptAsset)"
+      Filters="@(_AppPreloadEndpointFilter)"
+    >
+      <Output TaskParameter="FilteredEndpoints" ItemName="_AppPreloadScriptAssetEndpoint" />
+    </FilterStaticWebAssetEndpoints>
+    <UpdateStaticWebAssetEndpoints
+      EndpointsToUpdate="@(_AppPreloadScriptAssetEndpoint)"
+      AllEndpoints="@(_AppPreloadScriptAssetEndpoint)"
+      Operations="@(_AppendPreloadRelPreloadProperty);@(_AppendPreloadAsScriptProperty);@(_AppendPreloadPriorityHighProperty);@(_AppendPreloadCrossoriginAnonymousProperty)"
+    >
+      <Output TaskParameter="UpdatedEndpoints" ItemName="_UpdatedAppStaticWebAssetEndpoint" />
+    </UpdateStaticWebAssetEndpoints>
+    <ItemGroup>
+      <StaticWebAssetEndpoint Remove="@(_AppPreloadScriptAssetEndpoint)" />
+      <StaticWebAssetEndpoint Include="@(_UpdatedAppStaticWebAssetEndpoint)" />
+    </ItemGroup>
+  </Target>
 </Project>
diff --git a/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html b/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
index 8a30a27eb74e..1db8a4608ea9 100644
--- a/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
+++ b/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
@@ -7,6 +7,7 @@
   <title>WasmMySdk</title>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <link rel="preload">
   <script type="importmap"></script>
   <script type="module" src="main.js"></script>
   

From 9b4817de887e8a51512d7a15d46f69fe3d0778e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Tue, 1 Apr 2025 14:21:28 +0200
Subject: [PATCH 06/18] Optional filter by group

---
 .../Tasks/WriteImportMapToHtml.cs             | 31 +++++++++++++------
 .../VanillaWasm/wwwroot/index.html            |  2 +-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index a9c60d42b878..7670fc1f302f 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -46,7 +46,7 @@ public partial class WriteImportMapToHtml : Task
 
     private static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
 
-    private static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""\s*[/]?>");
+    private static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""(\id=""(?<group>[^""]+)"")?\s*[/]?>");
 
     public override bool Execute()
     {
@@ -81,7 +81,7 @@ public override bool Execute()
                 outputContent = _preloadRegex.Replace(outputContent, e =>
                 {
                     Log.LogMessage("Writing preload links to '{0}'", item.ItemSpec);
-                    return GeneratePreloadLinks(resources);
+                    return GeneratePreloadLinks(resources, e.Groups["group"]?.Value);
                 });
 
                 // Fingerprint all assets used in html
@@ -114,7 +114,7 @@ public override bool Execute()
         return true;
     }
 
-    private static string GeneratePreloadLinks(List<ResourceAsset> assets)
+    private static string GeneratePreloadLinks(List<ResourceAsset> assets, string? group)
     {
         var links = new List<(string? Order, string Value)>();
         foreach (var asset in assets)
@@ -124,26 +124,32 @@ private static string GeneratePreloadLinks(List<ResourceAsset> assets)
                 continue;
             }
 
-            string link = $"<link href=\"{asset.Url}\" rel=\"{asset.PreloadRel}\"";
+            if (group != null && asset.PreloadGroup != group)
+            {
+                continue;
+            }
+
+            var link = new StringBuilder();
+            link.Append($"<link href=\"{asset.Url}\" rel=\"{asset.PreloadRel}\"");
             if (!string.IsNullOrEmpty(asset.PreloadAs))
             {
-                link = String.Concat(link, " as=\"", asset.PreloadAs, "\"");
+                link.Append(" as=\"").Append(asset.PreloadAs).Append("\"");
             }
             if (!string.IsNullOrEmpty(asset.PreloadPriority))
             {
-                link = String.Concat(link, " fetchpriority=\"", asset.PreloadPriority, "\"");
+                link.Append(" fetchpriority=\"").Append(asset.PreloadPriority).Append("\"");
             }
             if (!string.IsNullOrEmpty(asset.PreloadCrossorigin))
             {
-                link = String.Concat(link, " crossorigin=\"", asset.PreloadCrossorigin, "\"");
+                link.Append(" crossorigin=\"").Append(asset.PreloadCrossorigin).Append("\"");
             }
             if (!string.IsNullOrEmpty(asset.Integrity))
             {
-                link = String.Concat(link, " integrity=\"", asset.Integrity, "\"");
+                link.Append(" integrity=\"").Append(asset.Integrity).Append("\"");
             }
 
-            link += " />";
-            links.Add((asset.PreloadOrder, link));
+            link.Append(" />");
+            links.Add((asset.PreloadOrder, link.ToString()));
         }
 
         links.Sort((a, b) => string.Compare(a.Order, b.Order, StringComparison.InvariantCulture));
@@ -185,6 +191,10 @@ internal List<ResourceAsset> CreateResourcesFromEndpoints(IEnumerable<StaticWebA
                     {
                         resourceAsset.Integrity = property.Value;
                     }
+                    else if (property.Name.Equals("preloadgroup", StringComparison.OrdinalIgnoreCase))
+                    {
+                        resourceAsset.PreloadGroup = property.Value;
+                    }
                     else if (property.Name.Equals("preloadrel", StringComparison.OrdinalIgnoreCase))
                     {
                         resourceAsset.PreloadRel = property.Value;
@@ -274,6 +284,7 @@ internal sealed class ResourceAsset(string url)
     public string Url { get; } = url;
     public string? Label { get; set; }
     public string? Integrity { get; set; }
+    public string? PreloadGroup { get; set; }
     public string? PreloadRel { get; set; }
     public string? PreloadAs { get; set; }
     public string? PreloadPriority { get; set; }
diff --git a/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html b/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
index 1db8a4608ea9..3193039a8b68 100644
--- a/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
+++ b/test/TestAssets/TestProjects/VanillaWasm/wwwroot/index.html
@@ -7,7 +7,7 @@
   <title>WasmMySdk</title>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <link rel="preload">
+  <link rel="preload" id="webassembly">
   <script type="importmap"></script>
   <script type="module" src="main.js"></script>
   

From a79722808182af535164c2f15beb7a7869de2803 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Tue, 1 Apr 2025 15:03:57 +0200
Subject: [PATCH 07/18] More StringBuilder

---
 .../Tasks/WriteImportMapToHtml.cs             | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index 7670fc1f302f..361fe60e5077 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -1,13 +1,13 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Text.RegularExpressions;
+using Microsoft.AspNetCore.StaticWebAssets.Tasks.Utils;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 using System.Text.Encodings.Web;
 using System.Text.Json.Serialization;
 using System.Text.Json;
-using Microsoft.AspNetCore.StaticWebAssets.Tasks.Utils;
+using System.Text.RegularExpressions;
 
 namespace Microsoft.AspNetCore.StaticWebAssets.Tasks;
 
@@ -42,11 +42,11 @@ public partial class WriteImportMapToHtml : Task
     // 2.group = fingerprint placeholder
     // 3.group = file extension
     // wrapped in quotes
-    private static readonly Regex _assetsRegex = new Regex(@"""([^""]+)(#\[\.{fingerprint}\])([^""]+)""");
+    internal static readonly Regex _assetsRegex = new Regex(@"""([^""]+)(#\[\.{fingerprint}\])([^""]+)""");
 
-    private static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
+    internal static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
 
-    private static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""(\id=""(?<group>[^""]+)"")?\s*[/]?>");
+    internal static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""(\sid=""(?<group>[^""]+)"")?\s*[/]?>");
 
     public override bool Execute()
     {
@@ -130,22 +130,22 @@ private static string GeneratePreloadLinks(List<ResourceAsset> assets, string? g
             }
 
             var link = new StringBuilder();
-            link.Append($"<link href=\"{asset.Url}\" rel=\"{asset.PreloadRel}\"");
+            link.Append($"<link href=\"").Append(asset.Url).Append("\" rel=\"").Append(asset.PreloadRel).Append('"');
             if (!string.IsNullOrEmpty(asset.PreloadAs))
             {
-                link.Append(" as=\"").Append(asset.PreloadAs).Append("\"");
+                link.Append(" as=\"").Append(asset.PreloadAs).Append('"');
             }
             if (!string.IsNullOrEmpty(asset.PreloadPriority))
             {
-                link.Append(" fetchpriority=\"").Append(asset.PreloadPriority).Append("\"");
+                link.Append(" fetchpriority=\"").Append(asset.PreloadPriority).Append('"');
             }
             if (!string.IsNullOrEmpty(asset.PreloadCrossorigin))
             {
-                link.Append(" crossorigin=\"").Append(asset.PreloadCrossorigin).Append("\"");
+                link.Append(" crossorigin=\"").Append(asset.PreloadCrossorigin).Append('"');
             }
             if (!string.IsNullOrEmpty(asset.Integrity))
             {
-                link.Append(" integrity=\"").Append(asset.Integrity).Append("\"");
+                link.Append(" integrity=\"").Append(asset.Integrity).Append('"');
             }
 
             link.Append(" />");

From 946576b72c0dd3174582f75b7bfc1b47ac301071 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Tue, 1 Apr 2025 15:04:09 +0200
Subject: [PATCH 08/18] Tests for regexes

---
 .../WriteImportMapToHtmlTest.cs               | 238 ++++++++++++++++++
 1 file changed, 238 insertions(+)
 create mode 100644 test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs

diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
new file mode 100644
index 000000000000..8be48c46fa5c
--- /dev/null
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
@@ -0,0 +1,238 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#nullable disable
+
+using Microsoft.AspNetCore.StaticWebAssets.Tasks;
+using System.Text.RegularExpressions;
+
+namespace Microsoft.AspNetCore.Razor.Tasks;
+
+public class WriteImportMapToHtmlTest
+{
+    [Theory]
+    [InlineData(
+        """
+        <script src="main#[.{fingerprint}].js"></script>
+        """,
+        true,
+        "main.js"
+    )]
+    [InlineData(
+        """
+        <script src="main#[.{fingerprint}].js">
+        </script>
+        """,
+        true,
+        "main.js"
+    )]
+    [InlineData(
+        """
+        <script    src="main#[.{fingerprint}].js"   >   </script>
+        """,
+        true,
+        "main.js"
+    )]
+    [InlineData(
+        """
+        <script src="./main#[.{fingerprint}].js"></script>
+        """,
+        true,
+        "./main.js"
+    )]
+    [InlineData(
+        """
+        <script src="./folder/folder/file.name.something#[.{fingerprint}].js"></script>
+        """,
+        true,
+        "./folder/folder/file.name.something.js"
+    )]
+    [InlineData(
+        """
+        <script src="main#[.{fingerprint}].suffix.js"></script>
+        """,
+        true,
+        "main.suffix.js"
+    )]
+    [InlineData(
+        """
+        <script src="main.js"></script>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <script src='main#[.{fingerprint}].js'></script>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <script src=main#[.{fingerprint}].js></script>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link href="main#[.{fingerprint}].js" rel="preload" as="script" fetchpriority="high" crossorigin="anonymous">
+        """,
+        true,
+        "main.js"
+    )]
+    public void ValidateAssetsRegex(string input, bool shouldMatch, string fileName = null)
+    {
+        var match = WriteImportMapToHtml._assetsRegex.Match(input);
+        Assert.Equal(shouldMatch, match.Success);
+
+        if (fileName != null)
+        {
+            Assert.Equal(fileName, match.Groups[1].Value + match.Groups[3].Value);
+        }
+    }
+
+    [Theory]
+    [InlineData(
+        """
+        <script type="importmap"></script>
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <script   type="importmap"   >   </script>
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <script type="importmap">
+        </script>
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <script type="importmap">
+        {
+            "imports": {
+            }
+        }
+        </script>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <script type=importmap></script>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <script type='importmap'></script>
+        """,
+        false
+    )]
+    public void ValidateImportMapRegex(string input, bool shouldMatch)
+    {
+        Assert.Equal(shouldMatch, WriteImportMapToHtml._importMapRegex.Match(input).Success);
+    }
+
+    [Theory]
+    [InlineData(
+        """
+        <link rel="preload"/>
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <link   rel="preload"    />
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <link    rel="preload">
+        """,
+        true
+    )]
+    [InlineData(
+        """
+        <link rel=preload />
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link rel='preload' />
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link rel="preload"
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link />"
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link>"
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link rel="preload" href="file.png" />
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link rel="preload" id="webassembly" />
+        """,
+        true,
+        "webassembly"
+    )]
+    [InlineData(
+        """
+        <link rel="preload" id="webassembly">
+        """,
+        true,
+        "webassembly"
+    )]
+    [InlineData(
+        """
+        <link rel="preload" id='webassembly'>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link rel="preload"id="webassembly" />
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <link id="webassembly" rel="preload" />
+        """,
+        false
+    )]
+    public void ValidatePreloadRegex(string input, bool shouldMatch, string group = null)
+    {
+        var match = WriteImportMapToHtml._preloadRegex.Match(input);
+        Assert.Equal(shouldMatch, match.Success);
+
+        if (group != null)
+        {
+            Assert.Equal(group, match.Groups["group"]?.Value);
+        }
+    }
+}

From e834aff5518262c9f7d83a1920a6f1ec115032c4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 09:51:19 +0200
Subject: [PATCH 09/18] Feedback

---
 src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs     | 9 ++-------
 .../StaticWebAssets/WriteImportMapToHtmlTest.cs          | 2 +-
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
index 361fe60e5077..7f28c1266a55 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
@@ -37,12 +37,7 @@ public partial class WriteImportMapToHtml : Task
     [Output]
     public string[] FileWrites { get; set; } = [];
 
-    // "([^"]+)(#\[\.{fingerprint}\])([^"]+)"
-    // 1.group = file name
-    // 2.group = fingerprint placeholder
-    // 3.group = file extension
-    // wrapped in quotes
-    internal static readonly Regex _assetsRegex = new Regex(@"""([^""]+)(#\[\.{fingerprint}\])([^""]+)""");
+    internal static readonly Regex _assetsRegex = new Regex(@"""(?<fileName>[^""]+)#\[\.{fingerprint}\](?<fileExtension>[^""]+)""");
 
     internal static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
 
@@ -87,7 +82,7 @@ public override bool Execute()
                 // Fingerprint all assets used in html
                 outputContent = _assetsRegex.Replace(outputContent, e =>
                 {
-                    string assetPath = e.Groups[1].Value + e.Groups[3].Value;
+                    string assetPath = e.Groups["fileName"].Value + e.Groups["fileExtension"].Value;
                     string fingerprintedAssetPath = GetFingerprintedAssetPath(urlMappings, assetPath);
                     Log.LogMessage("Replacing asset '{0}' with fingerprinted version '{1}'", assetPath, fingerprintedAssetPath);
                     return "\"" + fingerprintedAssetPath + "\"";
diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
index 8be48c46fa5c..92243dc3e98b 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
@@ -86,7 +86,7 @@ public void ValidateAssetsRegex(string input, bool shouldMatch, string fileName
 
         if (fileName != null)
         {
-            Assert.Equal(fileName, match.Groups[1].Value + match.Groups[3].Value);
+            Assert.Equal(fileName, match.Groups["fileName"].Value + match.Groups["fileExtension"].Value);
         }
     }
 

From 9929660d7c47692c9f7b3ec1abfc77f7b3bc21f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 09:53:15 +0200
Subject: [PATCH 10/18] One more test case

---
 .../StaticWebAssets/WriteImportMapToHtmlTest.cs            | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
index 92243dc3e98b..50b23c2f5ddc 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
@@ -54,6 +54,13 @@ public class WriteImportMapToHtmlTest
         true,
         "main.suffix.js"
     )]
+    [InlineData(
+        """
+        <script src="/root/main#[.{fingerprint}].suffix.js"></script>
+        """,
+        true,
+        "/root/main.suffix.js"
+    )]
     [InlineData(
         """
         <script src="main.js"></script>

From c9edacbfc1c8ee794c38290dac022df9cee7a790 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 10:13:20 +0200
Subject: [PATCH 11/18] Rename

---
 ...icWebAssets.HtmlAssetPlaceholders.targets} | 80 +++++++++----------
 .../Microsoft.NET.Sdk.StaticWebAssets.targets |  2 +-
 ...ml.cs => OverrideHtmlAssetPlaceholders.cs} |  2 +-
 ...s => OverrideHtmlAssetPlaceholdersTest.cs} |  8 +-
 4 files changed, 46 insertions(+), 46 deletions(-)
 rename src/StaticWebAssetsSdk/Targets/{Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets => Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets} (72%)
 rename src/StaticWebAssetsSdk/Tasks/{WriteImportMapToHtml.cs => OverrideHtmlAssetPlaceholders.cs} (99%)
 rename test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/{WriteImportMapToHtmlTest.cs => OverrideHtmlAssetPlaceholdersTest.cs} (93%)

diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
similarity index 72%
rename from src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
rename to src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
index 17d976d6ef43..906df597c420 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
@@ -1,6 +1,6 @@
 <!--
 ***********************************************************************************************
-Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets
+Microsoft.NET.Sdk.StaticWebAssets.OverrideHtmlAssetPlaceholders.targets
 
 WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and have
           created a backup copy.  Incorrect changes to this file will make it
@@ -12,69 +12,69 @@ Copyright (c) .NET Foundation. All rights reserved.
 
 <Project ToolsVersion="14.0">
     
-  <UsingTask TaskName="Microsoft.AspNetCore.StaticWebAssets.Tasks.WriteImportMapToHtml" AssemblyFile="$(StaticWebAssetsSdkBuildTasksAssembly)" />
+  <UsingTask TaskName="Microsoft.AspNetCore.StaticWebAssets.Tasks.OverrideHtmlAssetPlaceholders" AssemblyFile="$(StaticWebAssetsSdkBuildTasksAssembly)" />
 
   <PropertyGroup>
 
     <!--
         ResolveBuildRelatedStaticWebAssets
-          ResolveHtmlImportMapBuildStaticWebAssets
-            GenerateHtmlImportMapBuildStaticWebAssets
-              ResolveHtmlImportMapBuildConfiguration
+          ResolveHtmlAssetPlaceholdersBuildStaticWebAssets
+            GenerateHtmlAssetPlaceholdersBuildStaticWebAssets
+              ResolveHtmlAssetPlaceholdersBuildConfiguration
      -->
     <ResolveBuildRelatedStaticWebAssetsDependsOn>
       $(ResolveBuildRelatedStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapBuildStaticWebAssets;
+      ResolveHtmlAssetPlaceholdersBuildStaticWebAssets;
     </ResolveBuildRelatedStaticWebAssetsDependsOn>
     <ResolveCompressedFilesDependsOn>
       $(ResolveCompressedFilesDependsOn);
-      ResolveHtmlImportMapBuildStaticWebAssets
+      ResolveHtmlAssetPlaceholdersBuildStaticWebAssets
     </ResolveCompressedFilesDependsOn>
     <ResolveBuildServiceWorkerStaticWebAssetsDependsOn>
       $(ResolveBuildServiceWorkerStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapBuildStaticWebAssets
+      ResolveHtmlAssetPlaceholdersBuildStaticWebAssets
     </ResolveBuildServiceWorkerStaticWebAssetsDependsOn>
-    <ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
-      $(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn);
-      GenerateHtmlImportMapBuildStaticWebAssets
-    </ResolveHtmlImportMapBuildStaticWebAssetsDependsOn>
-    <GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
-      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapBuildConfiguration
-    </GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+    <ResolveHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
+      $(ResolveHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn);
+      GenerateHtmlAssetPlaceholdersBuildStaticWebAssets
+    </ResolveHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
+    <GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
+      $(GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn);
+      ResolveHtmlAssetPlaceholdersBuildConfiguration
+    </GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
 
     <!--
         ResolvePublishRelatedStaticWebAssets
-          ResolveHtmlImportMapPublishStaticWebAssets
-            GenerateHtmlImportMapPublishStaticWebAssets
-              ResolveHtmlImportMapPublishConfiguration
+          ResolveHtmlAssetPlaceholdersPublishStaticWebAssets
+            GenerateHtmlAssetPlaceholdersPublishStaticWebAssets
+              ResolveHtmlAssetPlaceholdersPublishConfiguration
      -->
     <ResolvePublishRelatedStaticWebAssetsDependsOn>
       $(ResolvePublishRelatedStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapPublishStaticWebAssets
+      ResolveHtmlAssetPlaceholdersPublishStaticWebAssets
     </ResolvePublishRelatedStaticWebAssetsDependsOn>
     <ResolvePublishCompressedStaticWebAssetsDependsOn>
       $(ResolvePublishCompressedStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapPublishStaticWebAssets
+      ResolveHtmlAssetPlaceholdersPublishStaticWebAssets
     </ResolvePublishCompressedStaticWebAssetsDependsOn>
     <ResolvePublishServiceWorkerStaticWebAssetsDependsOn>
       $(ResolvePublishServiceWorkerStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapPublishStaticWebAssets
+      ResolveHtmlAssetPlaceholdersPublishStaticWebAssets
     </ResolvePublishServiceWorkerStaticWebAssetsDependsOn>
-    <ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
-      $(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn);
-      GenerateHtmlImportMapPublishStaticWebAssets
-    </ResolveHtmlImportMapPublishStaticWebAssetsDependsOn>
-    <GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
-      $(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn);
-      ResolveHtmlImportMapPublishConfiguration
-    </GenerateHtmlImportMapPublishStaticWebAssetsDependsOn>
+    <ResolveHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn>
+      $(ResolveHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn);
+      GenerateHtmlAssetPlaceholdersPublishStaticWebAssets
+    </ResolveHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn>
+    <GenerateHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn>
+      $(GenerateHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn);
+      ResolveHtmlAssetPlaceholdersPublishConfiguration
+    </GenerateHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn>
 
   </PropertyGroup>
 
   <!-- Build -->
 
-  <Target Name="ResolveHtmlImportMapBuildConfiguration">
+  <Target Name="ResolveHtmlAssetPlaceholdersBuildConfiguration">
     <PropertyGroup>
       <_BuildImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'build'))</_BuildImportMapHtmlPath>
     </PropertyGroup>
@@ -95,8 +95,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     </FilterStaticWebAssetEndpoints>
   </Target>
 
-  <Target Name="GenerateHtmlImportMapBuildStaticWebAssets" DependsOnTargets="$(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)">
-    <WriteImportMapToHtml
+  <Target Name="GenerateHtmlAssetPlaceholdersBuildStaticWebAssets" DependsOnTargets="$(GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn)">
+    <OverrideHtmlAssetPlaceholders
       Assets="@(_EsModuleCandidate)"
       Endpoints="@(_EsModuleCandidateEndpoints)"
       IncludeOnlyHardFingerprintedModules="false"
@@ -105,10 +105,10 @@ Copyright (c) .NET Foundation. All rights reserved.
       <Output TaskParameter="HtmlCandidates" ItemName="_HtmlCandidates" />
       <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlFilesToRemove" />
       <Output TaskParameter="FileWrites" ItemName="FileWrites" />
-    </WriteImportMapToHtml>
+    </OverrideHtmlAssetPlaceholders>
   </Target>
 
-  <Target Name="ResolveHtmlImportMapBuildStaticWebAssets" DependsOnTargets="$(ResolveHtmlImportMapBuildStaticWebAssetsDependsOn)">
+  <Target Name="ResolveHtmlAssetPlaceholdersBuildStaticWebAssets" DependsOnTargets="$(ResolveHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn)">
     <ItemGroup>
       <_HtmlCandidatesNoMetadata
         Include="@(_HtmlCandidates)"
@@ -145,7 +145,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   
   <!-- Publish -->
 
-  <Target Name="ResolveHtmlImportMapPublishConfiguration">
+  <Target Name="ResolveHtmlAssetPlaceholdersPublishConfiguration">
     <PropertyGroup>
       <_PublishImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'publish'))</_PublishImportMapHtmlPath>
     </PropertyGroup>
@@ -165,8 +165,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     </FilterStaticWebAssetEndpoints>
   </Target>
 
-  <Target Name="GenerateHtmlImportMapPublishStaticWebAssets" DependsOnTargets="$(GenerateHtmlImportMapPublishStaticWebAssetsDependsOn)">
-    <WriteImportMapToHtml
+  <Target Name="GenerateHtmlAssetPlaceholdersPublishStaticWebAssets" DependsOnTargets="$(GenerateHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn)">
+    <OverrideHtmlAssetPlaceholders
       Assets="@(_EsModuleCandidateForPublish)"
       Endpoints="@(_EsModuleCandidateForPublishEndpoints)"
       IncludeOnlyHardFingerprintedModules="true"
@@ -175,10 +175,10 @@ Copyright (c) .NET Foundation. All rights reserved.
       <Output TaskParameter="HtmlCandidates" ItemName="_HtmlPublishCandidates" />
       <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlPublishFilesToRemove" />
       <Output TaskParameter="FileWrites" ItemName="FileWrites" />
-    </WriteImportMapToHtml>
+    </OverrideHtmlAssetPlaceholders>
   </Target>
 
-  <Target Name="ResolveHtmlImportMapPublishStaticWebAssets" DependsOnTargets="$(ResolveHtmlImportMapPublishStaticWebAssetsDependsOn)">
+  <Target Name="ResolveHtmlAssetPlaceholdersPublishStaticWebAssets" DependsOnTargets="$(ResolveHtmlAssetPlaceholdersPublishStaticWebAssetsDependsOn)">
     <ItemGroup>
       <_HtmlPublishCandidatesNoMetadata
         Include="@(_HtmlPublishCandidates)"
diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
index 2d9a75b49dea..63fe80d5ec10 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
@@ -741,6 +741,6 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <Import Project="Microsoft.NET.Sdk.StaticWebAssets.ServiceWorker.targets" Condition="'$(ServiceWorkerAssetsManifest)' != ''" />
 
-  <Import Project="Microsoft.NET.Sdk.StaticWebAssets.HtmlImportMap.targets" Condition="'$(WriteImportMapToHtml)' == 'true'" />
+  <Import Project="Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets" Condition="'$(OverrideHtmlAssetPlaceholders)' == 'true'" />
 
 </Project>
diff --git a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
similarity index 99%
rename from src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
rename to src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
index 7f28c1266a55..98b36e1c14fb 100644
--- a/src/StaticWebAssetsSdk/Tasks/WriteImportMapToHtml.cs
+++ b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
@@ -11,7 +11,7 @@
 
 namespace Microsoft.AspNetCore.StaticWebAssets.Tasks;
 
-public partial class WriteImportMapToHtml : Task
+public partial class OverrideHtmlAssetPlaceholders : Task
 {
     [Required]
     public ITaskItem[] Assets { get; set; } = [];
diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
similarity index 93%
rename from test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
rename to test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
index 50b23c2f5ddc..bc06a4aa2778 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/WriteImportMapToHtmlTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
@@ -8,7 +8,7 @@
 
 namespace Microsoft.AspNetCore.Razor.Tasks;
 
-public class WriteImportMapToHtmlTest
+public class OverrideHtmlAssetPlaceholdersTest
 {
     [Theory]
     [InlineData(
@@ -88,7 +88,7 @@ public class WriteImportMapToHtmlTest
     )]
     public void ValidateAssetsRegex(string input, bool shouldMatch, string fileName = null)
     {
-        var match = WriteImportMapToHtml._assetsRegex.Match(input);
+        var match = OverrideHtmlAssetPlaceholders._assetsRegex.Match(input);
         Assert.Equal(shouldMatch, match.Success);
 
         if (fileName != null)
@@ -142,7 +142,7 @@ public void ValidateAssetsRegex(string input, bool shouldMatch, string fileName
     )]
     public void ValidateImportMapRegex(string input, bool shouldMatch)
     {
-        Assert.Equal(shouldMatch, WriteImportMapToHtml._importMapRegex.Match(input).Success);
+        Assert.Equal(shouldMatch, OverrideHtmlAssetPlaceholders._importMapRegex.Match(input).Success);
     }
 
     [Theory]
@@ -234,7 +234,7 @@ public void ValidateImportMapRegex(string input, bool shouldMatch)
     )]
     public void ValidatePreloadRegex(string input, bool shouldMatch, string group = null)
     {
-        var match = WriteImportMapToHtml._preloadRegex.Match(input);
+        var match = OverrideHtmlAssetPlaceholders._preloadRegex.Match(input);
         Assert.Equal(shouldMatch, match.Success);
 
         if (group != null)

From e58f4a2eb310a7e1abfece25b13ff08066e7377d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 10:52:05 +0200
Subject: [PATCH 12/18] Rename 2

---
 ...StaticWebAssets.HtmlAssetPlaceholders.targets | 16 ++++++++--------
 .../StaticWebAssetsFingerprintingTest.cs         | 14 +++++++-------
 .../TestProjects/VanillaWasm/VanillaWasm.csproj  |  6 +++---
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
index 906df597c420..4b30a97bc7f2 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
@@ -76,10 +76,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <Target Name="ResolveHtmlAssetPlaceholdersBuildConfiguration">
     <PropertyGroup>
-      <_BuildImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'build'))</_BuildImportMapHtmlPath>
+      <_BuildHtmlAssetPlaceholdersPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'htmlassetplaceholders', 'build'))</_BuildHtmlAssetPlaceholdersPath>
     </PropertyGroup>
 
-    <MakeDir Directories="$(_BuildImportMapHtmlPath)"/>
+    <MakeDir Directories="$(_BuildHtmlAssetPlaceholdersPath)"/>
 
     <ItemGroup>
       <_HtmlStaticWebAssets Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Publish' and '%(Extension)' == '.html'" />
@@ -101,7 +101,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       Endpoints="@(_EsModuleCandidateEndpoints)"
       IncludeOnlyHardFingerprintedModules="false"
       HtmlFiles="@(_HtmlStaticWebAssets)"
-      OutputPath="$(_BuildImportMapHtmlPath)">
+      OutputPath="$(_BuildHtmlAssetPlaceholdersPath)">
       <Output TaskParameter="HtmlCandidates" ItemName="_HtmlCandidates" />
       <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlFilesToRemove" />
       <Output TaskParameter="FileWrites" ItemName="FileWrites" />
@@ -113,7 +113,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_HtmlCandidatesNoMetadata
         Include="@(_HtmlCandidates)"
         RemoveMetadata="SourceType;AssetKind;Integrity;Fingerprint" />
-      <_HtmlCandidatesNoMetadata ContentRoot="$(_BuildImportMapHtmlPath)" />
+      <_HtmlCandidatesNoMetadata ContentRoot="$(_BuildHtmlAssetPlaceholdersPath)" />
     </ItemGroup>
     <DefineStaticWebAssets CandidateAssets="@(_HtmlCandidatesNoMetadata)"
       SourceType="Computed"
@@ -147,10 +147,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <Target Name="ResolveHtmlAssetPlaceholdersPublishConfiguration">
     <PropertyGroup>
-      <_PublishImportMapHtmlPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'importmaphtml', 'publish'))</_PublishImportMapHtmlPath>
+      <_PublishHtmlAssetPlaceholdersPath>$([MSBuild]::NormalizeDirectory($(_StaticWebAssetsIntermediateOutputPath), 'htmlassetplaceholders', 'publish'))</_PublishHtmlAssetPlaceholdersPath>
     </PropertyGroup>
 
-    <MakeDir Directories="$(_PublishImportMapHtmlPath)"/>
+    <MakeDir Directories="$(_PublishHtmlAssetPlaceholdersPath)"/>
 
     <ItemGroup>
       <_EsModuleCandidateForPublish Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Build'" />
@@ -171,7 +171,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       Endpoints="@(_EsModuleCandidateForPublishEndpoints)"
       IncludeOnlyHardFingerprintedModules="true"
       HtmlFiles="@(_HtmlStaticWebAssets)"
-      OutputPath="$(_PublishImportMapHtmlPath)">
+      OutputPath="$(_PublishHtmlAssetPlaceholdersPath)">
       <Output TaskParameter="HtmlCandidates" ItemName="_HtmlPublishCandidates" />
       <Output TaskParameter="HtmlFilesToRemove" ItemName="_HtmlPublishFilesToRemove" />
       <Output TaskParameter="FileWrites" ItemName="FileWrites" />
@@ -183,7 +183,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_HtmlPublishCandidatesNoMetadata
         Include="@(_HtmlPublishCandidates)"
         RemoveMetadata="SourceType;AssetKind;Integrity;Fingerprint" />
-      <_HtmlPublishCandidatesNoMetadata ContentRoot="$(_PublishImportMapHtmlPath)" />
+      <_HtmlPublishCandidatesNoMetadata ContentRoot="$(_PublishHtmlAssetPlaceholdersPath)" />
     </ItemGroup>
     <DefineStaticWebAssets CandidateAssets="@(_HtmlPublishCandidatesNoMetadata)"
       SourceType="Computed"
diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
index 521b1021dd6f..67d09cad6ba3 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
@@ -46,7 +46,7 @@ public void Build_FingerprintsContent_WhenEnabled()
         AssertBuildAssets(manifest1, outputPath, intermediateOutputPath);
     }
 
-    public static TheoryData<string, string, string, bool, bool> WriteImportMapToHtmlData => new TheoryData<string, string, string, bool, bool>
+    public static TheoryData<string, string, string, bool, bool> OverrideHtmlAssetPlaceholdersData => new TheoryData<string, string, string, bool, bool>
     {
         { "VanillaWasm", "main.js", "main#[.{fingerprint}].js", true, true },
         { "VanillaWasm", "main.js", null, false, false },
@@ -54,15 +54,15 @@ public void Build_FingerprintsContent_WhenEnabled()
     };
 
     [Theory]
-    [MemberData(nameof(WriteImportMapToHtmlData))]
-    public void Build_WriteImportMapToHtml(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
+    [MemberData(nameof(OverrideHtmlAssetPlaceholdersData))]
+    public void Build_OverrideHtmlAssetPlaceholders(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
     {
         ProjectDirectory = CreateAspNetSdkTestAsset(testAsset, identifier: $"{testAsset}_{fingerprintUserJavascriptAssets}_{expectFingerprintOnScript}");
         ReplaceStringInIndexHtml(ProjectDirectory, scriptPath, scriptPathWithFingerprintPattern);
         FingerprintUserJavascriptAssets(fingerprintUserJavascriptAssets);
 
         var build = CreateBuildCommand(ProjectDirectory);
-        ExecuteCommand(build, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
+        ExecuteCommand(build, "-p:OverrideHtmlAssetPlaceholders=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
 
         var intermediateOutputPath = build.GetIntermediateDirectory(DefaultTfm, "Debug").ToString();
         var indexHtmlPath = Directory.EnumerateFiles(Path.Combine(intermediateOutputPath, "staticwebassets", "importmaphtml", "build"), "*.html").Single();
@@ -72,8 +72,8 @@ public void Build_WriteImportMapToHtml(string testAsset, string scriptPath, stri
     }
 
     [Theory]
-    [MemberData(nameof(WriteImportMapToHtmlData))]
-    public void Publish_WriteImportMapToHtml(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
+    [MemberData(nameof(OverrideHtmlAssetPlaceholdersData))]
+    public void Publish_OverrideHtmlAssetPlaceholders(string testAsset, string scriptPath, string scriptPathWithFingerprintPattern, bool fingerprintUserJavascriptAssets, bool expectFingerprintOnScript)
     {
         ProjectDirectory = CreateAspNetSdkTestAsset(testAsset, identifier: $"{testAsset}_{fingerprintUserJavascriptAssets}_{expectFingerprintOnScript}");
         ReplaceStringInIndexHtml(ProjectDirectory, scriptPath, scriptPathWithFingerprintPattern);
@@ -82,7 +82,7 @@ public void Publish_WriteImportMapToHtml(string testAsset, string scriptPath, st
         var projectName = Path.GetFileNameWithoutExtension(Directory.EnumerateFiles(ProjectDirectory.TestRoot, "*.csproj").Single());
 
         var publish = CreatePublishCommand(ProjectDirectory);
-        ExecuteCommand(publish, "-p:WriteImportMapToHtml=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
+        ExecuteCommand(publish, "-p:OverrideHtmlAssetPlaceholders=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
 
         var outputPath = publish.GetOutputDirectory(DefaultTfm, "Debug").ToString();
         var indexHtmlOutputPath = Path.Combine(outputPath, "wwwroot", "index.html");
diff --git a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
index f275acb37c94..7d1451ee76bb 100644
--- a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
+++ b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
@@ -2,10 +2,10 @@
   <PropertyGroup>
     <TargetFramework>$(CurrentTargetFramework)</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+    <GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
       _AddAppPreloadProperties;
-      $(GenerateHtmlImportMapBuildStaticWebAssetsDependsOn)
-    </GenerateHtmlImportMapBuildStaticWebAssetsDependsOn>
+      $(GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn)
+    </GenerateHtmlAssetPlaceholdersBuildStaticWebAssetsDependsOn>
   </PropertyGroup>
   <Target Name="_AppConfigurePreload">
     <ItemGroup>

From 52bbe4edd5f1e6578b4515f50eabf0abb7ed75f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 11:06:57 +0200
Subject: [PATCH 13/18] Consider order to be a number

---
 .../Tasks/OverrideHtmlAssetPlaceholders.cs               | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
index 98b36e1c14fb..02bf484222f4 100644
--- a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
+++ b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
@@ -208,7 +208,12 @@ internal List<ResourceAsset> CreateResourcesFromEndpoints(IEnumerable<StaticWebA
                     }
                     else if (property.Name.Equals("preloadorder", StringComparison.OrdinalIgnoreCase))
                     {
-                        resourceAsset.PreloadOrder = property.Value;
+                        if (!int.TryParse(property.Value, out int order))
+                        {
+                            order = 0;
+                        }
+
+                        resourceAsset.PreloadOrder = order;
                     }
                 }
 
@@ -284,7 +289,7 @@ internal sealed class ResourceAsset(string url)
     public string? PreloadAs { get; set; }
     public string? PreloadPriority { get; set; }
     public string? PreloadCrossorigin { get; set; }
-    public string? PreloadOrder { get; set; }
+    public int PreloadOrder { get; set; }
     public bool IsHardFingerprinted { get; set; } = true;
 }
 

From b16bc0010fefa22bbc75e2531b50701e0c8e6c7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 11:24:19 +0200
Subject: [PATCH 14/18] Fix

---
 src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
index 02bf484222f4..a272c2e8c3c5 100644
--- a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
+++ b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
@@ -111,7 +111,7 @@ public override bool Execute()
 
     private static string GeneratePreloadLinks(List<ResourceAsset> assets, string? group)
     {
-        var links = new List<(string? Order, string Value)>();
+        var links = new List<(int Order, string Value)>();
         foreach (var asset in assets)
         {
             if (asset.PreloadRel == null)
@@ -147,7 +147,7 @@ private static string GeneratePreloadLinks(List<ResourceAsset> assets, string? g
             links.Add((asset.PreloadOrder, link.ToString()));
         }
 
-        links.Sort((a, b) => string.Compare(a.Order, b.Order, StringComparison.InvariantCulture));
+        links.Sort((a, b) => a.Order.CompareTo(b.Order));
         return String.Join(Environment.NewLine, links.Select(l => l.Value));
     }
 

From d391f9c0b9dc935da570aa7a797e40656782fcb7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 12:53:14 +0200
Subject: [PATCH 15/18] Rename 3

---
 .../StaticWebAssetsFingerprintingTest.cs                        | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
index 67d09cad6ba3..15438446676a 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssetsFingerprintingTest.cs
@@ -65,7 +65,7 @@ public void Build_OverrideHtmlAssetPlaceholders(string testAsset, string scriptP
         ExecuteCommand(build, "-p:OverrideHtmlAssetPlaceholders=true", $"-p:FingerprintUserJavascriptAssets={fingerprintUserJavascriptAssets.ToString().ToLower()}").Should().Pass();
 
         var intermediateOutputPath = build.GetIntermediateDirectory(DefaultTfm, "Debug").ToString();
-        var indexHtmlPath = Directory.EnumerateFiles(Path.Combine(intermediateOutputPath, "staticwebassets", "importmaphtml", "build"), "*.html").Single();
+        var indexHtmlPath = Directory.EnumerateFiles(Path.Combine(intermediateOutputPath, "staticwebassets", "htmlassetplaceholders", "build"), "*.html").Single();
         var endpointsManifestPath = Path.Combine(intermediateOutputPath, $"staticwebassets.build.endpoints.json");
 
         AssertImportMapInHtml(indexHtmlPath, endpointsManifestPath, scriptPath, expectFingerprintOnScript: expectFingerprintOnScript, expectPreloadElement: testAsset == "VanillaWasm");

From e456ef2ca23937f355bfde8f05c5dc2eb3e368e7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 14:02:03 +0200
Subject: [PATCH 16/18] Update test to include preload group

---
 .../TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
index 7d1451ee76bb..eb60f30a679a 100644
--- a/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
+++ b/test/TestAssets/TestProjects/VanillaWasm/VanillaWasm.csproj
@@ -29,6 +29,11 @@
         <Name>PreloadCrossorigin</Name>
         <Value>anonymous</Value>
       </_AppendPreloadCrossoriginAnonymousProperty>
+      <_AppendPreloadGroupWebAssemblyProperty Include="Append">
+        <UpdateTarget>Property</UpdateTarget>
+        <Name>PreloadGroup</Name>
+        <Value>webassembly</Value>
+      </_AppendPreloadGroupWebAssemblyProperty>
     </ItemGroup>
   </Target>
   <Target Name="_AddAppPreloadProperties" DependsOnTargets="_AppConfigurePreload;_AddWasmStaticWebAssets" BeforeTargets="GenerateStaticWebAssetsManifest">
@@ -47,7 +52,7 @@
     <UpdateStaticWebAssetEndpoints
       EndpointsToUpdate="@(_AppPreloadScriptAssetEndpoint)"
       AllEndpoints="@(_AppPreloadScriptAssetEndpoint)"
-      Operations="@(_AppendPreloadRelPreloadProperty);@(_AppendPreloadAsScriptProperty);@(_AppendPreloadPriorityHighProperty);@(_AppendPreloadCrossoriginAnonymousProperty)"
+      Operations="@(_AppendPreloadRelPreloadProperty);@(_AppendPreloadAsScriptProperty);@(_AppendPreloadPriorityHighProperty);@(_AppendPreloadCrossoriginAnonymousProperty);@(_AppendPreloadGroupWebAssemblyProperty)"
     >
       <Output TaskParameter="UpdatedEndpoints" ItemName="_UpdatedAppStaticWebAssetEndpoint" />
     </UpdateStaticWebAssetEndpoints>

From 6fe643c68fa417d131e4c59cc50dec7ef24ec0ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Wed, 2 Apr 2025 14:51:58 +0200
Subject: [PATCH 17/18] Workaround before runtime knows about the rename

---
 ...oft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
index 4b30a97bc7f2..dee61365fd50 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.HtmlAssetPlaceholders.targets
@@ -14,6 +14,11 @@ Copyright (c) .NET Foundation. All rights reserved.
     
   <UsingTask TaskName="Microsoft.AspNetCore.StaticWebAssets.Tasks.OverrideHtmlAssetPlaceholders" AssemblyFile="$(StaticWebAssetsSdkBuildTasksAssembly)" />
 
+  <PropertyGroup>
+    <!-- Workaround until we update runtime -->
+    <WriteImportMapToHtml>true</WriteImportMapToHtml>
+  </PropertyGroup>
+
   <PropertyGroup>
 
     <!--

From ad7043349fdbd0c9750b1521090d8edc0bf63024 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Thu, 3 Apr 2025 14:36:38 +0200
Subject: [PATCH 18/18] Fix to allow multiple whitespaces between attributes.
 More tests

---
 .../Tasks/OverrideHtmlAssetPlaceholders.cs    |  2 +-
 .../OverrideHtmlAssetPlaceholdersTest.cs      | 45 +++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
index a272c2e8c3c5..e69a194c6407 100644
--- a/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
+++ b/src/StaticWebAssetsSdk/Tasks/OverrideHtmlAssetPlaceholders.cs
@@ -41,7 +41,7 @@ public partial class OverrideHtmlAssetPlaceholders : Task
 
     internal static readonly Regex _importMapRegex = new Regex(@"<script\s+type=""importmap""\s*>\s*</script>");
 
-    internal static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""(\sid=""(?<group>[^""]+)"")?\s*[/]?>");
+    internal static readonly Regex _preloadRegex = new Regex(@"<link\s+rel=""preload""(\s+id=""(?<group>[^""]+)"")?\s*[/]?>");
 
     public override bool Execute()
     {
diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
index bc06a4aa2778..31e709b85f12 100644
--- a/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/StaticWebAssets/OverrideHtmlAssetPlaceholdersTest.cs
@@ -79,6 +79,32 @@ public class OverrideHtmlAssetPlaceholdersTest
         """,
         false
     )]
+    [InlineData(
+        """
+        <h1>main#[.{fingerprint}].js</h1>
+        """,
+        false
+    )]
+    [InlineData(
+        """
+        <script>
+          var url = "main#[.{fingerprint}].js"
+        </script>
+        """,
+        true,
+        "main.js"
+    )]
+    [InlineData(
+        """
+        <script type='importmap'>{
+          "imports": {
+            "./main.js": "./main#[.{fingerprint}].js"
+          }
+        }</script>
+        """,
+        true,
+        "./main.js"
+    )]
     [InlineData(
         """
         <link href="main#[.{fingerprint}].js" rel="preload" as="script" fetchpriority="high" crossorigin="anonymous">
@@ -117,6 +143,15 @@ public void ValidateAssetsRegex(string input, bool shouldMatch, string fileName
         """,
         true
     )]
+    [InlineData(
+        """
+        <script
+         type="importmap"
+        >
+        </script>
+        """,
+        true
+    )]
     [InlineData(
         """
         <script type="importmap">
@@ -232,6 +267,16 @@ public void ValidateImportMapRegex(string input, bool shouldMatch)
         """,
         false
     )]
+    [InlineData(
+        """
+        <link
+         rel="preload"
+         id="webassembly"
+        />
+        """,
+        true,
+        "webassembly"
+    )]
     public void ValidatePreloadRegex(string input, bool shouldMatch, string group = null)
     {
         var match = OverrideHtmlAssetPlaceholders._preloadRegex.Match(input);