[davidfowl]

StaticHtmlRenderer.RenderElement did several case-insensitive comparisons for every element it wrote:

• textarea, form, option, select and script were each checked with string.Equals(..., OrdinalIgnoreCase);
• a lookup in a HashSet<string>(OrdinalIgnoreCase) of self-closing elements, which hashes the name case-insensitively.

Description

• Classify the element name once with a length-based switch into a small ElementKind enum. The comparisons are still OrdinalIgnoreCase, but most names are rejected by length alone.
• Remove the SelfClosingElements HashSet. The same 14 elements are matched in the switch.
• Read frame.ElementName into a local, and merge adjacent literal writes: '=' + '"' becomes "=\"", and ' ' + "action" + '=' + '"' becomes " action=\"".

The output is unchanged.

Benchmarks

I added HtmlRendererBenchmark in src/Components/Components/perf. It renders a 100-row table whose rows are child components, each with attributes, a checkbox and a link. The perf project now references Microsoft.AspNetCore.Components.Web.

Local BenchmarkDotNet, InProcess, 3 interleaved rounds against main:

Method	main	PR	Δ
WriteHtmlOnly (HTML writing only, to a StringWriter)	30.36 / 30.45 / 31.14 µs	27.71 / 28.01 / 27.85 µs	−9%
RenderAndWriteHtml (new renderer, render, then write)	106.5 / 118.6 / 119.1 µs	106.0 / 106.2 / 106.9 µs	noisy, ≤ main

Allocations are unchanged: 128 B and 144,760 B.

Tests

• Microsoft.AspNetCore.Components.Web.Tests: 330 passed, which includes the HtmlRenderer tests covering self-closing elements, textarea, select/option, form action and script.
• Microsoft.AspNetCore.Components.Endpoints.Tests: 883 passed.

🤖 Posted by ASP.NET Core Perf 2 (AI Agent)

[Copilot]

🔵 Needs a closer look

The required frozen review bundle and existing-feedback snapshot are missing, preventing verification of revision provenance and feedback deduplication.

No open issues 🎉

What changed in this PR

Optimizes static HTML rendering by classifying element names once, preserving existing case-insensitive handling and HTML output.

Changes:

• Replaces repeated element-name checks and the self-closing-element lookup with a length-based classifier.
• Combines adjacent literal writes for attributes and form actions.
• Adds benchmarks for HTML writing alone and rendering plus writing, with the required Components.Web project reference.

File	Description
src/​Components/​Web/​src/​HtmlRendering/​StaticHtmlRenderer.HtmlWriting.cs	Adds element classification and combines literal writes.
src/​Components/​Components/​perf/​Microsoft.AspNetCore.Components.Performance.csproj	References Components.Web for renderer benchmarks.
src/​Components/​Components/​perf/​HtmlRendererBenchmark.cs	Adds two benchmarks using a 100-row component table.

_{Review effort: Balanced}

[davidfowl]

Compliance check: no public API changes (ElementKind is a private enum). The output is identical. All element checks still use StringComparison.OrdinalIgnoreCase, and the length switch covers exactly the same 14 self-closing elements as the removed HashSet. The merged literal writes (=\", action=\") produce the same characters.

🤖 Posted by ASP.NET Core Perf 2 (AI Agent)

[PureWeen]

/review