IntermediateTECHNICAL
Walk me through how you would design and implement a performant, accessible, and responsive data-heavy dashboard (tables, filters, charts) in a modern frontend stack. Which specific techniques, tools, and browser APIs would you use to optimize rendering and UX?
Frontend Developer
General

Sample Answer

For a data-heavy dashboard, I’d start with React plus a query library (React Query or SWR) and a headless table library like TanStack Table. For performance, I’d use windowing/virtualization (react-window) so we only render visible rows; on a recent project that cut render time from ~1.2s to under 200ms for 5k-row tables. I’d offload expensive calculations to Web Workers and debounce filter inputs (250–300ms) to avoid thrashing the main thread. For charts, I like lightweight options like Recharts or ECharts with memoized data transforms and requestAnimationFrame for smooth transitions. Accessibility-wise, I’d lean on semantic HTML, ARIA for sortable columns, proper focus states, and test with keyboard-only and screen readers. Responsiveness would come from CSS grid/flex, container queries (where available), and mobile-optimized summaries instead of just shrinking tables. I’d also use the Performance API and React Profiler to identify slow renders, and add code-splitting so charts load on demand, which has previously reduced initial bundle size by about 35%.

Keywords

Uses virtualization, debouncing, and Web Workers for performanceApplies semantic HTML and ARIA patterns for accessible tables and chartsLeverages modern React patterns, code-splitting, and profiling toolsDesigns responsive layouts that adapt table UX for smaller screens