Replace regex prop counter with TypeScript compiler API

Uses ts.createProgram to parse real AST instead of regex + brace-depth
state machine. Immune to comments, strings, and complex type syntax.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/check-component-props.mjs

@@ -9,11 +9,14 @@
  * Only scans component files (not hooks, adapters, etc.) and only
  * counts properties declared directly in *Props interfaces — inherited
  * or extended HTML attributes are not counted.
+ *
+ * Uses the TypeScript compiler API for accurate AST-based counting,
+ * immune to comments, strings, and complex type syntax.
  */
 
 import { execSync } from "node:child_process";
-import { readFileSync } from "node:fs";
 import { relative } from "node:path";
+import ts from "typescript";
 
 const MAX_PROPS = 8;
 
@@ -25,66 +28,38 @@ const files = execSync(
 	.split("\n")
 	.filter(Boolean);
 
+const program = ts.createProgram(files, {
+	target: ts.ScriptTarget.ESNext,
+	module: ts.ModuleKind.ESNext,
+	jsx: ts.JsxEmit.ReactJSX,
+	strict: true,
+	noEmit: true,
+	skipLibCheck: true,
+});
+
 let errors = 0;
 
-const propsRegex = /^(?:export\s+)?interface\s+(\w+Props)\s*\{/;
-
 for (const file of files) {
-	const content = readFileSync(file, "utf-8");
-	const lines = content.split("\n");
+	const sourceFile = program.getSourceFile(file);
+	if (!sourceFile) continue;
 
-	let inInterface = false;
-	let interfaceName = "";
-	let braceDepth = 0;
-	let parenDepth = 0;
-	let propCount = 0;
-	let startLine = 0;
+	ts.forEachChild(sourceFile, (node) => {
+		if (!ts.isInterfaceDeclaration(node)) return;
+		if (!node.name.text.endsWith("Props")) return;
 
-	for (let i = 0; i < lines.length; i++) {
-		const line = lines[i];
+		const propCount = node.members.filter((m) =>
+			ts.isPropertySignature(m),
+		).length;
 
-		if (!inInterface) {
-			const match = propsRegex.exec(line);
-			if (match) {
-				inInterface = true;
-				interfaceName = match[1];
-				braceDepth = 0;
-				parenDepth = 0;
-				propCount = 0;
-				startLine = i + 1;
-			}
+		if (propCount > MAX_PROPS) {
+			const rel = relative(process.cwd(), file);
+			const { line } = sourceFile.getLineAndCharacterOfPosition(node.name.pos);
+			console.error(
+				`${rel}:${line + 1}: ${node.name.text} has ${propCount} props (max ${MAX_PROPS})`,
+			);
+			errors++;
 		}
-
-		if (inInterface) {
-			for (const ch of line) {
-				if (ch === "{") braceDepth++;
-				if (ch === "}") braceDepth--;
-				if (ch === "(") parenDepth++;
-				if (ch === ")") parenDepth--;
-			}
-
-			// Count prop lines at brace depth 1 and not inside function params:
-			// Matches "  propName?: type" and "  readonly propName: type"
-			if (
-				braceDepth === 1 &&
-				parenDepth === 0 &&
-				/^\s+(?:readonly\s+)?\w+\??\s*:/.test(line)
-			) {
-				propCount++;
-			}
-
-			if (braceDepth === 0) {
-				if (propCount > MAX_PROPS) {
-					const rel = relative(process.cwd(), file);
-					console.error(
-						`${rel}:${startLine}: ${interfaceName} has ${propCount} props (max ${MAX_PROPS})`,
-					);
-					errors++;
-				}
-				inInterface = false;
-			}
-		}
-	}
+	});
 }
 
 if (errors > 0) {