102. Data Fetching Dashboard with Exponential Backoff

Build a Data Fetching Dashboard in React that loads metrics from a mock API, shows shimmer placeholders while loading, and retries with exponential backoff on failures.

1. Dashboard Layout

• Render summary cards (Revenue, Active Users, Conversion Rate, Refunds)
• Render a recent activity list
• Display a "Last updated" timestamp when data loads successfully

2. Loading State (Shimmer)

• Show shimmer skeletons for cards and activity rows while loading
• Keep shimmer visible during retries until data loads

3. Error Handling with Exponential Backoff

• Retry failed requests automatically with exponential backoff
• Base delay: 500ms
• Retry attempts: max 4 total attempts
• Backoff formula: delay = baseDelay * 2^attempt
• Show a retry status message while waiting for the next attempt
• Provide a "Retry now" button to restart immediately

4. Cancellation & Cleanup

• Cancel in-flight requests on unmount or when starting a new retry
• Clear timers when a retry is aborted or succeeds

Data Shape

interface DashboardData {
  summary: {
    label: string;
    value: string;
    delta: string;
  }[];
  activity: {
    id: string;
    title: string;
    time: string;
  }[];
  lastUpdated: string;
}

Example Mock Data

{
  summary: [
    { label: 'Revenue', value: '$84.2k', delta: '+12%' },
    { label: 'Active Users', value: '3,412', delta: '+4%' }
  ],
  activity: [
    { id: '1', title: 'Invoice #4821 paid', time: '2m ago' }
  ],
  lastUpdated: '2024-06-04T12:05:00Z'
}