Test(dashboard): handle empty error fallbacks safely

app/(root)/dashboard/error.empty-fallback.test.tsx

@@ -0,0 +1,79 @@
+// app/(root)/dashboard/error.empty-fallback.test.tsx
+
+import { describe, expect, it, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom/vitest';
+
+vi.mock('next/link', () => ({
+  default: ({
+    children,
+    ...props
+  }: React.AnchorHTMLAttributes<HTMLAnchorElement> & { children: React.ReactNode }) => (
+    <a {...props}>{children}</a>
+  ),
+}));
+
+import DashboardError from './error';
+
+describe('Dashboard Error Page - Empty & Missing Input Fallbacks', () => {
+  it('renders successfully when error is null', () => {
+    expect(() =>
+      render(<DashboardError error={null as unknown as Error} reset={vi.fn()} />)
+    ).not.toThrow();
+
+    expect(screen.getByRole('heading', { name: 'Something went wrong' })).toBeInTheDocument();
+    expect(
+      screen.getByText('An unexpected error occurred while fetching the dashboard data.')
+    ).toBeInTheDocument();
+    expect(screen.getByText('⚠️')).toBeInTheDocument();
+  });
+
+  it('renders successfully when error is undefined', () => {
+    expect(() =>
+      render(<DashboardError error={undefined as unknown as Error} reset={vi.fn()} />)
+    ).not.toThrow();
+
+    expect(screen.getByRole('heading', { name: 'Something went wrong' })).toBeInTheDocument();
+    expect(
+      screen.getByText('An unexpected error occurred while fetching the dashboard data.')
+    ).toBeInTheDocument();
+  });
+
+  it('renders successfully when error is an empty object', () => {
+    expect(() =>
+      render(<DashboardError error={{} as unknown as Error} reset={vi.fn()} />)
+    ).not.toThrow();
+
+    expect(screen.getByRole('heading', { name: 'Something went wrong' })).toBeInTheDocument();
+    expect(
+      screen.getByText('An unexpected error occurred while fetching the dashboard data.')
+    ).toBeInTheDocument();
+  });
+
+  it('renders successfully when error has no message property', () => {
+    expect(() =>
+      render(<DashboardError error={{ name: 'CustomError' } as unknown as Error} reset={vi.fn()} />)
+    ).not.toThrow();
+
+    expect(screen.getByRole('heading', { name: 'Something went wrong' })).toBeInTheDocument();
+    expect(
+      screen.getByText('An unexpected error occurred while fetching the dashboard data.')
+    ).toBeInTheDocument();
+  });
+
+  it('renders successfully when error message is an empty string', () => {
+    expect(() => render(<DashboardError error={new Error('')} reset={vi.fn()} />)).not.toThrow();
+
+    expect(screen.getByRole('heading', { name: 'Something went wrong' })).toBeInTheDocument();
+    expect(
+      screen.getByText('An unexpected error occurred while fetching the dashboard data.')
+    ).toBeInTheDocument();
+  });
+
+  it('renders interactive elements correctly in fallback state', () => {
+    render(<DashboardError error={{} as unknown as Error} reset={vi.fn()} />);
+
+    expect(screen.getByRole('button', { name: /try again/i })).toBeInTheDocument();
+    expect(screen.getByRole('link', { name: /go back home/i })).toBeInTheDocument();
+  });
+});

app/(root)/dashboard/error.tsx

@@ -11,12 +11,16 @@ export default function DashboardError({
   reset: () => void;
 }) {
   useEffect(() => {
-    console.error(error);
+    if (error) {
+      console.error(error);
+    }
   }, [error]);
 
-  const isRateLimit = error.message.includes('API limit') || error.message.includes('rate limit');
+  const errorMessage = error?.message || '';
 
-  const isNotFound = error.message.includes('not found');
+  const isRateLimit = errorMessage.includes('API limit') || errorMessage.includes('rate limit');
+
+  const isNotFound = errorMessage.includes('not found');
 
   return (
     <div className="min-h-[80vh] flex flex-col items-center justify-center p-6 text-center">
@@ -38,7 +42,7 @@ export default function DashboardError({
             ? "We couldn't find a GitHub user with that username. Please check the spelling and try again."
             : isRateLimit
               ? "GitHub's API rate limit has been reached. Please add a GITHUB_TOKEN to your environment variables to increase the limit, or try again later."
-              : error.message || 'An unexpected error occurred while fetching the dashboard data.'}
+              : errorMessage || 'An unexpected error occurred while fetching the dashboard data.'}
         </p>
 
         <div className="flex flex-col gap-3">