refactor(laroux): add return types to various functions for improved type safety

- Updated error response functions in api-types.ts to explicitly define return types.
- Enhanced build error functions in types.ts with return types for better clarity.
- Added return type annotations to createIsolatedWriter in build-validator.ts.
- Specified return types for methods in error-boundary.tsx, error-overlay.tsx, lazy-loader.ts, image.tsx, and renderer.ts for consistency and type safety.

Author: eser

pkg/@eser/laroux-bundler/domain/build-validator.ts

@@ -196,11 +196,19 @@ export function isWithinOutputDir(
     resolvedFilePath === resolvedDistDir;
 }
 
+/**
+ * Isolated writer interface for build output
+ */
+export type IsolatedWriter = {
+  writeTextFile(filePath: string, content: string): Promise<void>;
+  copy(src: string, dest: string): Promise<void>;
+};
+
 /**
  * Create a safe write function that only allows writes to dist/
  * Use this to wrap file writes for strict isolation
  */
-export function createIsolatedWriter(distDir: string) {
+export function createIsolatedWriter(distDir: string): IsolatedWriter {
   const resolvedDistDir = runtime.path.resolve(distDir);
 
   return {

pkg/@eser/laroux-bundler/types.ts

@@ -91,23 +91,23 @@ export class BuildError extends Error {
  */
 export const buildErrors = {
   /** CSS processing error */
-  cssError: (reason: string) =>
+  cssError: (reason: string): BuildError =>
     new BuildError(
       `CSS processing failed: ${reason}`,
       "BUILD104",
       "Check your CSS files and configuration.",
     ),
 
   /** Module not found */
-  moduleNotFound: (modulePath: string) =>
+  moduleNotFound: (modulePath: string): BuildError =>
     new BuildError(
       `Module not found: ${modulePath}`,
       "BUILD100",
       "Check that the file exists and the import path is correct.",
     ),
 
   /** Build failed */
-  buildFailed: (reason: string) =>
+  buildFailed: (reason: string): BuildError =>
     new BuildError(
       `Build failed: ${reason}`,
       "BUILD101",

pkg/@eser/laroux-react/client/bootstrap/error-boundary.tsx

@@ -69,12 +69,12 @@ export class ErrorBoundary extends Component<Props, State> {
     });
   }
 
-  handleRetry = () => {
+  handleRetry = (): void => {
     // Reload the page to retry
     globalThis.location.reload();
   };
 
-  render() {
+  render(): React.ReactNode {
     if (this.state.hasError) {
       // For network errors, don't show visible error UI - just return null
       // This keeps SSR content visible and prevents Lighthouse score penalty

pkg/@eser/laroux-react/client/bootstrap/error-overlay.tsx

@@ -16,7 +16,7 @@ interface ErrorInfo {
   column?: number;
 }
 
-export function ErrorOverlay() {
+export function ErrorOverlay(): React.ReactElement | null {
   const [error, setError] = useState<ErrorInfo | null>(null);
 
   useEffect(() => {

pkg/@eser/laroux-react/client/bootstrap/lazy-loader.ts

@@ -336,7 +336,12 @@ export class LazyChunkLoader {
   /**
    * Get loading statistics (for debugging)
    */
-  getStats() {
+  getStats(): {
+    totalChunks: number;
+    loadedChunks: number;
+    loadingChunks: number;
+    cachedModules: number;
+  } {
     return {
       totalChunks: Object.keys(this.manifest.files).length,
       loadedChunks: this.loadedChunks.size,

pkg/@eser/laroux-react/runtime/image/image.tsx

@@ -37,7 +37,7 @@ export { ImageSizes };
  * - Decoding async for better performance
  * - fetchpriority for above-the-fold images
  */
-export function Image(props: ImageProps) {
+export function Image(props: ImageProps): React.ReactElement {
   const {
     src,
     fallback,
@@ -113,7 +113,9 @@ export function Image(props: ImageProps) {
  * Server Component - Responsive image with aspect ratio container
  * Prevents layout shift with CSS aspect-ratio
  */
-export function ResponsiveImage(props: ResponsiveImageProps) {
+export function ResponsiveImage(
+  props: ResponsiveImageProps,
+): React.ReactElement {
   const {
     src,
     alt,

pkg/@eser/laroux-server/adapters/react/html-shell.ts

@@ -150,4 +150,5 @@ export function createReactHtmlShellBuilder(): HtmlShellBuilder {
 /**
  * Default React HTML shell builder instance
  */
-export const reactHtmlShellBuilder = createReactHtmlShellBuilder();
+export const reactHtmlShellBuilder: HtmlShellBuilder =
+  createReactHtmlShellBuilder();

pkg/@eser/laroux-server/adapters/react/renderer.ts

@@ -149,4 +149,4 @@ export function createReactRenderer(): Renderer {
 /**
  * Default React renderer instance
  */
-export const reactRenderer = createReactRenderer();
+export const reactRenderer: Renderer = createReactRenderer();

pkg/@eser/laroux/router/api-types.ts

@@ -95,14 +95,17 @@ export function errorResponse(
  * Standard HTTP error responses
  */
 export const HttpError = {
-  badRequest: (message = "Bad Request") => errorResponse(message, 400),
-  unauthorized: (message = "Unauthorized") => errorResponse(message, 401),
-  forbidden: (message = "Forbidden") => errorResponse(message, 403),
-  notFound: (message = "Not Found") => errorResponse(message, 404),
-  methodNotAllowed: (message = "Method Not Allowed") =>
+  badRequest: (message = "Bad Request"): Response =>
+    errorResponse(message, 400),
+  unauthorized: (message = "Unauthorized"): Response =>
+    errorResponse(message, 401),
+  forbidden: (message = "Forbidden"): Response => errorResponse(message, 403),
+  notFound: (message = "Not Found"): Response => errorResponse(message, 404),
+  methodNotAllowed: (message = "Method Not Allowed"): Response =>
     errorResponse(message, 405),
-  conflict: (message = "Conflict") => errorResponse(message, 409),
-  unprocessable: (message = "Unprocessable Entity") =>
+  conflict: (message = "Conflict"): Response => errorResponse(message, 409),
+  unprocessable: (message = "Unprocessable Entity"): Response =>
     errorResponse(message, 422),
-  internal: (message = "Internal Server Error") => errorResponse(message, 500),
+  internal: (message = "Internal Server Error"): Response =>
+    errorResponse(message, 500),
 };