⚛️ Frontend Refactor & Performance

Current bundle: 3.2MB JavaScript taking 8-12 seconds to load on 3G connection. All routes and components loaded upfront. Implement code splitting: 1) Route-based splitting with React.lazy() 2) Vendor chunking (separate React, libraries) 3) Dynamic imports for heavy components (charts, editors) 4) Preloading for anticipated navigation. Target: <500KB initial bundle, <2s FCP. Use webpack bundle analyzer to identify large modules. Also: lazy load images, defer non-critical JS, async load third-party scripts (analytics, chat). Measure: Lighthouse score (target 90+), bundle size budget in CI. Expected improvement: 60% faster initial load. 8 story points. High impact on user experience.

Implement code splitting and lazy loading for faster initial load

User dashboard rendering 2000+ items causing 5+ second freeze, browser becoming unresponsive. DOM has 20,000+ elements. Implement virtual scrolling to render only visible items. Use react-window or react-virtualized. Features: 1) Dynamic height items 2) Scroll position restoration 3) Keyboard navigation 4) Search/filter support. Also optimize: memo expensive renders, use React.memo, implement windowing for table view. Expected: render 10K items with <100ms freeze, constant memory usage regardless of list size. Test: lists with 10K, 50K items. Also implement: pagination as alternative, infinite scroll for mobile. 8 story points. Critical for enterprise users with large datasets.

Implement virtual scrolling for large lists (1000+ items)

Unhandled errors crash entire app showing white screen. No error boundaries, no graceful degradation. Implement: 1) Root error boundary for catastrophic errors 2) Route-level boundaries for page failures 3) Component boundaries for isolated failures 4) Async boundaries for data fetching errors. Features: error reporting to Sentry, retry button, fallback UI, error details in dev mode. Handle: render errors, event handler errors, async errors (with error boundary). Also add: custom 404 page, network error page, maintenance mode page. Test: simulate errors in different components, verify isolation. Document: error boundary best practices. 5 story points. Improves reliability and UX.

Implement proper error boundaries and fallback UIs

Styled-components causing performance issues: runtime style injection, large bundle size (+50KB), increased React tree depth, slower server rendering. Migrate to CSS Modules or vanilla CSS. Benefits: 1) No runtime overhead 2) Smaller bundle size 3) Better performance 4) Static CSS extraction. Migration: convert styled-components to CSS Modules, use CSS variables for theming, PostCSS for autoprefixer. Challenges: lose dynamic styling (workaround: CSS variables), separate files. Use: TypeScript for CSS Module typing, CSS nesting, CSS minification. Expected: 20-30ms faster initial render, 50KB smaller bundle. Gradual migration starting with new components. 13 story points.

Migrate from CSS-in-JS to CSS Modules for better performance

Codebase is 80K lines of JavaScript, frequent runtime errors that TypeScript would catch. Recent production bugs: undefined property access, wrong function arguments, typos in object keys. Plan: gradual migration starting with new code, then incrementally convert existing files. Phase 1: Setup TypeScript config, convert utility functions and types. Phase 2: Convert React components (props, state typing). Phase 3: Convert Redux (typed actions, reducers). Phase 4: Strict mode, no 'any' types. Benefits: catch errors at compile time, better IDE autocomplete, self-documenting code, safer refactoring. Challenges: learning curve, existing bugs revealed, third-party library types. Use: strict: true, noImplicitAny, strictNullChecks. Est: 21 story points over 3 sprints.

Migrate from JavaScript to TypeScript for type safety

Redux becoming maintenance burden: boilerplate code, async logic complex, duplicated state (server data in Redux and cache). Proposal: migrate to React Query for server state + Context for local UI state. Benefits: 1) Automatic caching, background refetch 2) Optimistic updates built-in 3) Less boilerplate 4) Better TypeScript support 5) Devtools for debugging. Migration plan: route by route, starting with dashboard. Keep Redux for global UI state (theme, modals). React Query for: API calls, data fetching, mutations. Context for: user preferences, current filters. Remove: Redux sagas, custom API middleware. Estimated 13 story points. Requires team training on React Query patterns.

Refactor state management from Redux to React Query + Context

Still on React 17, missing: automatic batching, transitions API, suspense improvements, concurrent rendering. Plan: 1) Upgrade to React 18 2) Switch to createRoot 3) Adopt new features: useTransition for non-urgent updates, useDeferredValue for expensive renders, startTransition for state updates. Benefits: better performance, smoother UI during heavy computation, improved Suspense. Testing: regression test all components, particularly: forms, animations, third-party integrations. Known issues: some libraries not compatible, need updates. Also upgrade: React Router (v5 → v6), React Redux (v7 → v8). Estimated: 13 story points. Test thoroughly in staging.

Upgrade from React 17 to React 18 with concurrent features

Performance profiler shows excessive re-renders: parent component state change causing all children to re-render, 50+ component renders for single state change. Issues: 1) Props changing every render (new object/array/function) 2) No memoization for expensive components 3) Context value changing unnecessarily 4) Inline functions in JSX. Optimizations: 1) React.memo for pure components 2) useMemo for expensive calculations 3) useCallback for stable function references 4) Split context to avoid unnecessary updates 5) Use state colocation. Profile: React DevTools Profiler, identify hotspots. Target: <16ms render time for 60fps. Document: performance patterns and anti-patterns. 8 story points.

Optimize React re-renders with profiling and memoization

Users want offline access, installable app, push notifications. Implement PWA: 1) Service worker for caching 2) Offline mode with local storage 3) Install prompt 4) Push notifications 5) Background sync. Cache strategy: network-first for API, cache-first for assets, stale-while-revalidate for content. Features: offline indicator, sync status, conflict resolution when back online. Use: Workbox for service worker, IndexedDB for large data, localStorage for settings. Manifest: app name, icons, theme colors, display mode. Test: offline scenarios, update mechanism, notification permission. Lighthouse PWA score target: 100. 13 story points. Major feature for mobile users.

Implement Progressive Web App (PWA) with offline support

Accessibility audit shows major violations: no keyboard navigation, missing ARIA labels, poor color contrast, no screen reader support. Goal: WCAG 2.1 AA compliance. Fix: 1) Semantic HTML everywhere 2) Keyboard navigation (focus management, tab order) 3) ARIA labels and roles 4) Color contrast 4.5:1 minimum 5) Screen reader testing. Tools: axe DevTools, WAVE, Lighthouse. Features: skip links, focus indicators, descriptive alt text, form labels, error announcements. Test: keyboard only navigation, screen reader (NVDA, JAWS), automated tests (jest-axe). Document: accessibility guidelines for team. Legal requirement in many jurisdictions. 13 story points. High priority.

Implement comprehensive accessibility (WCAG 2.1 AA compliance)

Current forms using controlled components, re-rendering on every keystroke, complex validation logic, 300+ line form components. Migrate to React Hook Form: Benefits: 1) Uncontrolled inputs (better performance) 2) Built-in validation 3) Less code 4) TypeScript support 5) Easy integration with UI libraries. Features: field-level validation, async validation, form state management, error handling. Migrate: login, signup, user profile, settings forms (12 forms total). Integration with existing validation schemas (Yup). Also: better error messages, loading states, success feedback. Expected: 50% less form code, smoother typing experience. 8 story points.

Refactor forms to use React Hook Form for better performance

UI regressions slipping through: button misaligned, text overflow, responsive breakpoint broken. No visual testing, relying on manual QA. Implement visual regression testing: 1) Integrate Percy or Chromatic with CI 2) Snapshot key pages and components 3) Review visual diffs in PR 4) Multiple viewports (mobile, tablet, desktop) 5) Cross-browser testing. Setup: snapshots for login, dashboard, settings, checkout flow. Thresholds: flag changes >0.1% pixels. Include: Storybook integration for component snapshots. Review process: approve/reject visual changes before merge. Cost: ~$149/month for Percy. Prevents UI bugs reaching production. 5 story points.

Setup automated visual regression testing with Percy or Chromatic

Components lack documentation, hard to develop in isolation, designers can't preview components. Implement Storybook: 1) Storybook setup with TypeScript 2) Stories for all reusable components 3) Controls for props 4) Different states/variants 5) Accessibility addon 6) Docs addon for auto-generated docs. Benefits: component playground, visual regression testing, design system documentation, easier onboarding. Also: integrate with Chromatic for visual testing, publish Storybook to URL for stakeholders. Include: action logging, viewport addon for responsive testing. Document: how to write stories. 8 story points. Improves DX and design-dev collaboration.

Setup Storybook for component development and documentation

Images account for 60% of page weight (8MB), slow page loads, high bandwidth costs. Implement: 1) Convert to WebP (80% smaller than PNG) 2) Responsive images (srcset) 3) Lazy loading (native loading='lazy') 4) Image CDN (Cloudinary or Imgix) 5) Blur placeholder during load. Optimization pipeline: upload → resize → compress → convert to WebP → serve via CDN. Support fallback to PNG for old browsers. Also: lazy load offscreen images, use thumbnail for list view, full size on click. Expected: 70% reduction in image size, 40% faster page load. Update: profile pictures, blog images, product photos. 5 story points. High impact.

Implement image optimization with lazy loading and WebP format

Current loading: generic spinner everywhere, no indication of what's loading, jarring content shift when data appears. Implement: 1) Skeleton screens matching content layout 2) Granular loading states (per section) 3) Optimistic UI updates 4) Progressive loading (show data as it arrives) 5) Loading error states. Use: React Suspense for declarative loading, skeleton libraries or custom CSS. Pages to update: dashboard, user profile, search results, article view. Also: loading progress indicators for long operations, timeout handling. Expected: better perceived performance, reduced rage clicks. 5 story points. UX improvement.

Inbox

⚛️ Frontend Refactor & Performance

Backlog

In Progress

Code Review

Testing

Done