▸case-01 We are upgrading our web app dashboard to Next.js 15 and need a live feed component that renders server-side and updates asynchronously. Can you help us design and code a streaming user activity panel? Please provide complete TypeScript code, optimistic feedback transitions, skeleton loading states, proper keyboard and screen reader accessibility markup, and usage documentation showing how to integrate it into our App Router page. | fail→fail | 31,639 | 39,104 | +24% | 1 | 1 | 0% | 6,676 | 7,845 | +18% | 0 | 0 | — |
▸case-02 Our e-commerce product gallery page is lagging badly on mobile devices, specifically suffering from high Largest Contentful Paint and layout shifts when dynamic filters are applied. I need a frontend code refactor using React 19 patterns. Please provide a production-ready component solution with typed props, responsive Tailwind layout handling, client-side state hooks for quick filtering, and a list of performance validation steps to ensure strong Core Web Vitals. | fail→fail | 32,238 | 24,744 | -23% | 1 | 1 | 0% | 6,171 | 6,049 | -2% | 0 | 0 | — |
▸case-03 I need to build an interactive, multi-step customer onboarding checkout form that uses Server Actions for submission and instant validation feedback. Please write the complete TypeScript React component, including accessible focus management, semantic ARIA attributes for form errors, resilient fallback boundary patterns, and a matching Storybook story file to test all states in isolation. | fail→fail | 38,004 | 36,840 | -3% | 1 | 1 | 0% | 8,254 | 9,749 | +18% | 0 | 0 | — |
▸case-04 We need a social post feedback button in a Next.js 15 App Router app where clicking 'Like' updates the count instantly on screen while calling a server mutation. What React 19 hook should we use for instant UI response before server confirmation, and how should it be coded? | fail→fail | 13,336 | 16,539 | +24% | 1 | 1 | 0% | 2,606 | 4,820 | +85% | 0 | 0 | — |
▸case-05 We are building a Next.js 15 dashboard page that displays user profiles and allows interactive search filtering. We want to know whether to make the entire page a client component or split server and client boundaries. Show the component structure with code. | fail→fail | 18,083 | 24,672 | +36% | 1 | 1 | 0% | 3,296 | 6,810 | +107% | 0 | 0 | — |
▸case-06 Create a custom select dropdown component in React with TypeScript and Tailwind CSS for a design system. Users should be able to navigate options using arrow keys, space, and enter, and screen readers must announce selection changes. | fail→fail | 23,816 | 29,952 | +26% | 1 | 1 | 0% | 5,134 | 7,755 | +51% | 0 | 0 | — |
▸case-07 We need a lightweight client-side state management solution for a React application to handle atomic state changes (like modal visibility and user preferences) without re-rendering unrelated component trees. Show how to implement this using an atomic state library. | fail→fail | 14,739 | 20,679 | +40% | 1 | 1 | 0% | 2,622 | 5,649 | +115% | 0 | 0 | — |
▸case-08 We have an enterprise React SPA (not Next.js) that fetches remote REST APIs and needs automatic revalidation on window focus, background polling, and request deduplication. What data fetching library should we use and how do we set up a hook for user data? | pass→pass | 16,317 | 16,873 | +3% | 1 | 1 | 0% | 3,012 | 4,802 | +59% | 0 | 0 | — |
▸case-09 We need to build a user profile edit form in React 19 that handles pending form submit states and server validation errors returned from a form action function. | fail→fail | 15,683 | 20,420 | +30% | 1 | 1 | 0% | 3,208 | 5,920 | +85% | 0 | 0 | — |
▸case-10 Our Next.js 15 hero banner image causes significant Cumulative Layout Shift (CLS) and slow Largest Contentful Paint (LCP) on mobile landing pages. How should we configure the image component and layout to eliminate CLS and maximize LCP speed? | pass→pass | 19,622 | 16,926 | -14% | 1 | 1 | 0% | 3,252 | 4,429 | +36% | 0 | 0 | — |
▸case-11 We have a heavy interactive charting component (using Chart.js/Recharts) that bloats our initial bundle size on a Next.js 15 page. How can we delay loading this component until it enters viewport or initial page render finishes without blocking HTML streaming? | fail→pass | 17,135 | 26,660 | +56% | 1 | 1 | 0% | 3,127 | 5,828 | +86% | 0 | 0 | — |
▸case-12 In a React 19 application, filtering a large list of 5,000 table rows causes UI freezing during text input typing. How do we keep the text input instantly responsive while processing list filtering in the background? | fail→fail | 15,944 | 16,554 | +4% | 1 | 1 | 0% | 2,893 | 4,756 | +64% | 0 | 0 | — |
▸case-13 We need to protect all /dashboard/* routes in a Next.js 15 App Router app, redirecting unauthenticated requests to /login based on a JWT session cookie. | pass→pass | 12,833 | 16,555 | +29% | 1 | 1 | 0% | 2,593 | 4,839 | +87% | 0 | 0 | — |
▸case-14 Build a theme switcher component in React with Tailwind CSS that supports light mode, dark mode, and system default preference without causing flash of unstyled content (FOUC). | fail→fail | 20,519 | 21,198 | +3% | 1 | 1 | 0% | 4,271 | 6,034 | +41% | 0 | 0 | — |
▸case-15 We need dynamic SEO titles, descriptions, and OpenGraph social images generated per product on our Next.js 15 App Router dynamic route /products/[slug]. | pass→pass | 17,980 | 26,674 | +48% | 1 | 1 | 0% | 3,577 | 7,278 | +103% | 0 | 0 | — |
▸case-16 Build an accessible modal dialog in React with TypeScript that locks scroll on open, trapping focus inside the modal and closing on Escape key press or backdrop click. | pass→pass | 20,026 | 24,869 | +24% | 1 | 1 | 0% | 4,398 | 6,918 | +57% | 0 | 0 | — |
▸case-17 Build a paginated list in React that automatically loads more items as the user scrolls to the bottom of the page using remote API pagination. | fail→fail | 14,869 | 23,693 | +59% | 1 | 1 | 0% | 2,955 | 6,526 | +121% | 0 | 0 | — |
▸case-18 We need to connect a React client component to a real-time server activity stream and append new activity items smoothly with loading indicators and reconnection handling. | fail→fail | 21,020 | 23,462 | +12% | 1 | 1 | 0% | 4,364 | 6,545 | +50% | 0 | 0 | — |
▸case-19 Show how to write a reusable React Error Boundary in TypeScript that catches runtime JS errors in child components, logs them to a monitoring service, and displays a fallback UI with a retry button. | pass→pass | 16,313 | 15,165 | -7% | 1 | 1 | 0% | 3,481 | 4,716 | +35% | 0 | 0 | — |
▸case-20 We have a card component that needs to render in a narrow single-column sidebar as stacked, but when placed in a wide main content grid, it should display side-by-side layout based on its container width rather than viewport width. | fail→pass | 10,636 | 17,954 | +69% | 1 | 1 | 0% | 2,148 | 5,021 | +134% | 0 | 0 | — |
▸case-21 Write a server action in Next.js 15 App Router that updates user account settings in the database and immediately updates the cached path data across the application. | pass→pass | 16,855 | 22,298 | +32% | 1 | 1 | 0% | 3,570 | 5,487 | +54% | 0 | 0 | — |
▸case-22 Write a button component with primary, secondary, loading, and disabled variants using React, TypeScript, and Tailwind, and provide a full Storybook file for it. | fail→pass | 18,642 | 20,502 | +10% | 1 | 1 | 0% | 4,049 | 6,021 | +49% | 0 | 0 | — |
▸case-23 Design a PostgreSQL database schema and SQL query pattern for a multi-tenant user authentication microservice. | pass→pass | 24,693 | 25,173 | +2% | 1 | 1 | 0% | 5,014 | 6,621 | +32% | 0 | 0 | — |
▸case-24 Write a native Apple Watch user interface component in SwiftUI for real-time heart rate monitoring. | pass→fail | 18,670 | 13,385 | -28% | 1 | 1 | 0% | 3,592 | 4,291 | +19% | 0 | 0 | — |
▸case-25 Create a visual design system color token hierarchy and typography spec for export to Figma tokens. | pass→fail | 23,625 | 28,851 | +22% | 1 | 1 | 0% | 5,085 | 8,151 | +60% | 0 | 0 | — |