Dev notes
A second performance pass, this time focused on runtime rendering costs rather than network-level vitals. Context value instability, resize handler allocation, GPU-heavy CSS, unbounded DOM growth, and transition waste. Working through these incrementally.
The first performance pass (the other thoughts page) focused on Core Web Vitals: TTFB, LCP, FCP, CLS, INP. Network-level, load-time stuff. This pass is different. It came from profiling the running app and looking at what happens after the page loads — rendering cost, GPU pressure, memory growth, and wasted reconciliation.
The review surfaced 18 issues across four priority tiers. This page documents the fixes as they land.
The WeatherProvider was creating a new context value object on every render. The toggle and setSelectedEffect callbacks were also recreated every render since they weren't wrapped in useCallback.
Any state change in the provider — weather data resolving, the user toggling effects — forced every consumer to re-render. That includes WeatherCanvas (800+ lines of canvas animation logic) and the header menu component. The canvas effect's useEffect deps are primitives so it didn't re-run the teardown/setup cycle, but the component still reconciled on every provider state change.
The fix: wrap toggle and setSelectedEffect in useCallback, then wrap the entire context value object in useMemo keyed on its actual values. Now consumers only re-render when a value they care about actually changes.
The resize event listener on the weather canvas fired on every frame during a window drag-resize. Each invocation reset the canvas dimensions (clearing the buffer), called effect.resize(), and for the cloud effect that meant recreating all 14 cloud positions and calling makeCloudSprite 14 times — each one allocating an offscreen document.createElement('canvas') with gradient fills.
That's dozens of canvas allocations per second during a resize drag. GC pressure spikes and visible frame drops on mid-range devices.
The fix: debounce the resize handler at 150ms. The canvas stays at its old size during the drag and snaps to the final dimensions once the user stops. The debounce timer is cleaned up in the effect teardown so there's no stale callback after unmount.
Every FeatureCard had backdrop-filter: blur(16px) applied via inline style. The section renders 11 cards. backdrop-filter: blur() is one of the most expensive CSS compositor operations — it rasterizes the content behind each element, applies a Gaussian blur kernel, and composites. With 11 elements visible simultaneously, that's significant GPU memory pressure.
The Gaussian blur kernel cost scales with the square of the radius. Reducing from 16px to 4px is roughly 1/16th the computation per card. Across 11 cards, that's a major reduction in per-frame compositor work while preserving the frosted glass aesthetic.
Both the TCG card browser and the GraphQL Pokémon grid use infinite scroll that appends pages to a flat CSS grid. After several pages, the DOM reaches 1000+ nodes all rendered simultaneously — images decoded, styles recalculated, paint layers composited for elements no one can see.
Full virtualization (@tanstack/react-virtual) would be heavy to retrofit into responsive CSS grids. Instead, both card components now use content-visibility: auto with contain-intrinsic-size. This is a browser-native CSS property that tells the compositor to skip rendering for offscreen elements entirely — no paint, no layout, no style recalculation. The browser can also release image decode buffers at its discretion. No JavaScript, no IntersectionObserver, no new dependencies.
transition-all forces the browser to check every CSS property for changes on every animation frame, even when only one or two properties actually change. Eight production components were still using it: the landing page hero and footer auth buttons, the operator dashboard stock bar and store card, the NBA section slide dots, both playoff pick cards, and the matchup prediction bar.
Each one was replaced with an explicit property list matching what actually transitions: transition-[border-color,background-color] for hover effects, transition-[width,background-color] for progress bars, transition-[opacity,border-color] for card containers. The browser now only tracks properties that can actually change.
The Clear and Storm weather effects normalize mouse coordinates by dividing clientX/clientY by window.innerWidth/window.innerHeight on every mousemove event (60+ Hz). These property accesses can force layout reflow if there are pending style changes.
The fix: pass the cached canvas dimensions (which already match the viewport from the resize handler) into setMouse instead of reading window.innerWidth/innerHeight from the DOM on every event.
The operator dashboard runs four concurrent polling intervals — stores every 30s, alerts every 15s, inventory every 60s, and a fleet summary every 15s. All four continued firing when the tab was hidden. On mobile, where browsers aggressively throttle background tabs, these requests pile up and fire in bursts when the tab regains focus.
The fix is a single property: refetchIntervalInBackground: false. TanStack Query checks document.hidden and automatically pauses polling when the tab isn't visible. Combined with the existing refetchOnWindowFocus: true, the dashboard refreshes immediately when the user returns and resumes its normal polling cadence.
Seven hooks were deriving their loading flag from isLoading || isFetching. In TanStack Query, isFetching is true during background refetches too — not just the initial load. So every 15-30s poll cycle briefly flashed a skeleton or spinner even when cached data was already on screen.
The fix: use isLoading alone for skeleton/spinner states. It's only true when there's no cached data (the genuine initial load). The existing RefreshBar component already handles the subtle “updating” indicator independently via isFetching.
All 13 learn topic pages eagerly imported their full content component (500-1400 lines each, 13k lines total). Since page.tsx is a server component that rendered the client component directly, Next.js bundled the entire content component into the route chunk — all demo logic, SVG data, and animation code downloaded before anything appeared.
Each page now wraps its content in next/dynamic with ssr: false. The content components are entirely interactive and require client-side JavaScript anyway, so there's no SEO cost. The route chunk now contains only metadata, and the heavy content loads asynchronously.
Three list-item components were missing React.memo: the operator dashboard's StoreCard, the TCG browser's CardTile, and the GraphQL grid's PokemonCard.
The operator dashboard polls every 30 seconds. When the parent re-renders with fresh data, all 4+ store cards reconcile even if only one store's data changed. Similarly, when the TCG browser loads the next page, every card on every previous page re-renders because the parent state changed.
Wrapping each in React.memo lets React skip reconciliation for items whose props haven't changed. The calendar components already used memo correctly — these three were the gaps.
Each of the 11 FeatureCard instances passed an inline object to Framer Motion's whileHover prop: {{ y: -4, transition: { ...spring.snappy } }}. Every render created a new object and spread spring.snappy into a new transition object. Framer Motion internally diffs gesture handler objects to detect changes, so 11 fresh objects meant 11 unnecessary diffs per render.
The fix: extract to a single module-level constant HOVER_ANIMATION. One allocation at module load, stable reference across all renders and all card instances.
The landing page can have up to 7 separate R3F Canvas instances — one per section model. While ModelLazyMount deferred creation and PauseWhenOffscreen paused rendering, each context still consumed GPU memory for its framebuffer even when paused. Browsers limit WebGL contexts to roughly 8–16 before evicting old ones. On mobile devices with stricter limits (often 4–8), scrolling the full page could trigger context loss events — models flickering or going black.
The previous ModelLazyMount was one-shot: it mounted on first intersection and never unmounted. The fix makes it bidirectional. It now uses a single IntersectionObserver with a 1000px root margin. When the container enters that margin the canvas mounts; when it leaves, the canvas unmounts and the WebGL context is released. The hero globe stays always-mounted (it's the first thing users see), so the worst case is 1 permanent context plus at most 2–3 nearby section contexts — well within every device's limit.
The review flagged that 41 components import from framer-motion (~32kb gzipped). Because it's imported in the root layout's providers and in so many leaf components, it's in the shared chunk and loaded on every page. Pages like /learn/two-pointers pull in the full motion library for just fadeInUp entrance animations that could be CSS.
The potential fix would be CSS @starting-style transitions or Framer Motion's m + LazyMotion pattern to tree-shake unused features. But the tradeoff doesn't justify the churn: refactoring 41 files for a library that's already in the shared chunk of a portfolio site. The cost is paid once on first load and cached. Leaving this as a documented decision rather than a fix.
All four operator hooks (useOperatorStores, useOperatorAlerts, useOperatorInventory, useOperatorActivity) used data ?? [] as a fallback during loading. The inline [] creates a new array reference on every render when data is undefined. Any consumer using the result in a dependency array or memo comparison sees a “change” on every render during the loading phase.
The fix: each hook now has a module-level typed EMPTY constant. Same stable reference across all renders, no unnecessary downstream re-renders during initial load.
The hero section had three inline style objects that depended on the current theme (dark vs light): the radial vignette gradient, the H1 text-shadow, and the subtitle text-shadow. Each created a new object reference on every render, triggering Framer Motion's internal prop diffing unnecessarily.
The fix: six module-level constants (dark and light variants for each). The component selects the right one with a ternary. Stable references, zero allocations per render.
Nine learn pages use setInterval for their “Play” auto-step feature (15 intervals total across demos like binary search, sliding window, trees, etc.). All properly clear intervals via refs, but none paused when the tab was hidden. A user clicking Play and switching tabs would have the animation silently complete in the background.
The fix: a document.hidden guard at the top of each interval callback. When the tab is hidden the callback returns immediately, skipping the step advancement. The interval keeps ticking (so cleanup is unchanged) but no state updates fire until the user is actually watching.
The review identified additional rendering optimizations still to be addressed. These will be documented here as they land.