[Web] Add Global Error Boundary with Retry Mechanism

.Jules/changelog.md

@@ -7,6 +7,7 @@
 ## [Unreleased]
 
 ### Added
+- Global `ErrorBoundary` component with dual-theme support to catch runtime errors and provide a "Try Again" or "Go Home" recovery option.
 - Inline form validation in Auth page with real-time feedback and proper ARIA accessibility support (`aria-invalid`, `aria-describedby`, `role="alert"`).
 - Dashboard skeleton loading state (`DashboardSkeleton`) to improve perceived performance during data fetch.
 - Comprehensive `EmptyState` component for Groups and Friends pages to better guide new users.

.Jules/knowledge.md

@@ -459,6 +459,30 @@ _Document errors and their solutions here as you encounter them._
 
 ## Recent Implementation Reviews
 
+### ✅ Successful PR Pattern: Error Boundary Implementation (#237)
+
+**Date:** 2026-01-13
+**Context:** Review of Error Boundary implementation
+
+**What was implemented:**
+1. Created `ErrorBoundary` class component (required for error catching)
+2. Created `ErrorFallback` functional component (for hooks/theme support)
+3. Integrated into `App.tsx` wrapping `AppRoutes` but inside Providers
+4. Built-in dual-theme support (Neo/Glass)
+
+**Why it succeeded:**
+- ✅ Separated Logic (Class) from UI (Function) to support hooks
+- ✅ Leveraged existing `useTheme` context
+- ✅ Provided clear recovery options (Reload, Go Home)
+- ✅ Integrated safe fallback UI
+
+**Key learnings:**
+- React Error Boundaries *must* be class components
+- To use hooks (like `useTheme`) in the fallback UI, create a separate functional component
+- Wrap specific routes rather than the entire app to keep Providers active (like Theme/Auth)
+
+---
+
 ### ✅ Successful PR Pattern: Toast Notification System (#227)
 
 **Date:** 2026-01-13

.Jules/todo.md

@@ -34,12 +34,12 @@
   - Impact: Guides new users, makes app feel polished
   - Size: ~70 lines
 
-- [ ] **[ux]** Error boundary with retry for API failures
-  - Files: Create `web/components/ErrorBoundary.tsx`, wrap app
+- [x] **[ux]** Error boundary with retry for API failures
+  - Completed: 2026-01-13
+  - Files modified: `web/components/ErrorBoundary.tsx`, `web/App.tsx`
   - Context: Catch errors gracefully with retry button
   - Impact: App doesn't crash, users can recover
-  - Size: ~60 lines
-  - Added: 2026-01-01
+  - Size: ~80 lines
 
 ### Mobile
 

web/App.tsx

@@ -6,6 +6,7 @@ import { AuthProvider, useAuth } from './contexts/AuthContext';
 import { ThemeProvider } from './contexts/ThemeContext';
 import { ToastProvider } from './contexts/ToastContext';
 import { ToastContainer } from './components/ui/Toast';
+import { ErrorBoundary } from './components/ErrorBoundary';
 import { Auth } from './pages/Auth';
 import { Dashboard } from './pages/Dashboard';
 import { Friends } from './pages/Friends';
@@ -51,8 +52,10 @@ const App = () => {
       <ToastProvider>
         <AuthProvider>
           <HashRouter>
+            <ErrorBoundary>
               <AppRoutes />
               <ToastContainer />
+            </ErrorBoundary>
           </HashRouter>
         </AuthProvider>
       </ToastProvider>

web/components/ErrorBoundary.tsx

@@ -0,0 +1,97 @@
+import React, { Component, ReactNode } from 'react';
+import { useTheme } from '../contexts/ThemeContext';
+import { THEMES } from '../constants';
+import { Button } from './ui/Button';
+import { AlertTriangle, RefreshCw, Home } from 'lucide-react';
+
+interface ErrorFallbackProps {
+  error: Error | null;
+  resetError: () => void;
+}
+
+const ErrorFallback: React.FC<ErrorFallbackProps> = ({ error, resetError }) => {
+  const { style, mode } = useTheme();
+
+  const isNeo = style === THEMES.NEOBRUTALISM;
+  const isDark = mode === 'dark';
+
+  let containerClasses = "";
+  if (isNeo) {
+    containerClasses = `border-2 border-black shadow-[8px_8px_0px_0px_rgba(0,0,0,1)] bg-white ${isDark ? 'bg-zinc-800 text-white' : 'text-black'}`;
+  } else {
+    containerClasses = `rounded-2xl border border-white/10 shadow-2xl backdrop-blur-xl ${isDark ? 'bg-black/60 text-white' : 'bg-white/60 text-gray-900'}`;
+  }
+
+  return (
+    <div className="min-h-screen flex items-center justify-center p-4">
+      <div className={`w-full max-w-md p-8 text-center ${containerClasses}`}>
+        <div className={`mb-6 flex justify-center`}>
+          <div className={`p-4 rounded-full ${isNeo ? 'border-2 border-black bg-neo-second' : 'bg-red-500/20 text-red-500'}`}>
+            <AlertTriangle size={48} className={isNeo ? 'text-black' : ''} />
+          </div>
+        </div>
+
+        <h2 className={`text-2xl font-bold mb-2 ${isNeo ? 'uppercase font-mono tracking-wider' : ''}`}>
+          Something went wrong
+        </h2>
+
+        <p className={`mb-6 ${isDark ? 'text-gray-300' : 'text-gray-600'}`}>
+          {error?.message || "An unexpected error occurred. We're sorry for the inconvenience."}
+        </p>
+
+        <div className="flex flex-col gap-3">
+          <Button onClick={resetError} className="w-full">
+            <RefreshCw size={18} />
+            Try Again
+          </Button>
+
+          <Button
+            variant="ghost"
+            onClick={() => window.location.href = '/'}
+            className="w-full"
+          >
+            <Home size={18} />
+            Back to Home
+          </Button>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+interface ErrorBoundaryProps {
+  children: ReactNode;
+}
+
+interface ErrorBoundaryState {
+  hasError: boolean;
+  error: Error | null;
+}
+
+export class ErrorBoundary extends Component<ErrorBoundaryProps, ErrorBoundaryState> {
+  constructor(props: ErrorBoundaryProps) {
+    super(props);
+    this.state = { hasError: false, error: null };
+  }
+
+  static getDerivedStateFromError(error: Error): ErrorBoundaryState {
+    return { hasError: true, error };
+  }
+
+  componentDidCatch(error: Error, errorInfo: React.ErrorInfo) {
+    console.error("Uncaught error:", error, errorInfo);
+  }
+
+  resetError = () => {
+    this.setState({ hasError: false, error: null });
+    window.location.reload();
+  };
+
+  render() {
+    if (this.state.hasError) {
+      return <ErrorFallback error={this.state.error} resetError={this.resetError} />;
+    }
+
+    return this.props.children;
+  }
+}