feat(site): extract api reference from components (#464)

site/scripts/api-docs-builder/src/html-handler.ts

@@ -0,0 +1,33 @@
+import * as ts from 'typescript';
+import type { HtmlExtraction } from './types.js';
+
+/** Extract tagName from a Lit element file. */
+export function extractHtml(filePath: string, program: ts.Program, componentName: string): HtmlExtraction | null {
+  const sourceFile = program.getSourceFile(filePath);
+  if (!sourceFile) return null;
+
+  let tagName = '';
+
+  function visit(node: ts.Node) {
+    if (ts.isClassDeclaration(node) && node.name?.text === `${componentName}Element`) {
+      for (const member of node.members) {
+        if (
+          ts.isPropertyDeclaration(member) &&
+          member.name &&
+          ts.isIdentifier(member.name) &&
+          member.name.text === 'tagName' &&
+          member.modifiers?.some((m) => m.kind === ts.SyntaxKind.StaticKeyword) &&
+          member.initializer &&
+          ts.isStringLiteral(member.initializer)
+        ) {
+          tagName = member.initializer.text;
+        }
+      }
+    }
+    ts.forEachChild(node, visit);
+  }
+
+  visit(sourceFile);
+
+  return tagName ? { tagName } : null;
+}