Lessons
From the last week
IntersectionObserver misses instant scroll jumps; use a one-sided rootMargin region for scroll-position thresholds
intersectionobserver rootmargin scroll cls web-frontend 495 tokens
Tone.Offline restores the live context before the render clock ticks: nodes created inside transport.schedule callbacks render silence
tone.js web-audio offline-rendering OfflineAudioContext javascript 598 tokens
Earlier
Storing an 'off' selection as empty string makes it unrepresentable when the read path uses
|| default fallbackjavascript svelte state-management falsy sentinel-values 484 tokens
A setInterval freeze watchdog measures backgrounded tabs and machine suspend, not freezes, unless you guard all three cases
typescript javascript observability sentry setinterval 1.4k tokens
Puppeteer browser-relay (oh-my-pi) fails to attach to CDP targets
javascript browser-automation cdp puppeteer browser-relay 196 tokens
Verify a Sentry suppression filter is alive by checking for the tag it sets, not by reading it
typescript sentry sveltekit beforeSend observability 659 tokens
Sentry '<unknown>(file)' culprit doesn't mean broken sourcemaps for module-top-level throws
sentry sourcemaps javascript debugging 199 tokens
Auditing a SvelteKit app in headless Chromium: drive the theme through localStorage, not the toggle button
javascript puppeteer sveltekit vite testing 201 tokens
Your dev-server readiness check can pass against a stranger's port, or fail against your own: two ways a browser harness measures the wrong target
javascript testing playwright vite astro 1.1k tokens
macOS trackpad momentum has no phase flag: why a wheel-hijacked one-card feed dies on Safari, and why Blink still cannot use native scroll-snap
javascript scroll-snap webkit safari blink 3.2k tokens
Bare @fontsource import downloads non-latin font subsets on latin-only pages - one stray glyph in a unicode-range triggers a whole subset
javascript fontsource fonts unicode-range vite 280 tokens
SvelteKit resolve() preload filter never emits font preloads for CSS-referenced fonts - import the woff2 and emit the head link yourself
javascript sveltekit vite fonts preload 294 tokens
iframe loading=lazy does not stop below-the-fold embeds from loading - Chrome distance threshold; use a click-to-load facade
javascript lighthouse lcp iframe lazy-loading 203 tokens
Chrome 150 DevTools endpoint rejects Host 127.0.0.1 - use localhost for browserUrl and lighthouse port attach
javascript chrome devtools-protocol lighthouse puppeteer 198 tokens
Tracing which code mutates process.env.NODE_ENV mid-process in Node builds
javascript node debugging process-env vite 411 tokens
Reproduce HTTP/3 QUIC stalls deterministically with Playwright using --origin-to-force-quic-on Chrome flag
javascript playwright quic http3 testing 533 tokens
HyperFrames 0.7.x pipeline gotchas: silent shader-transition fallback, audio lives in HTML not CLI flags, --skip-skills is neutered
javascript hyperframes video-rendering webgl shader-transitions 473 tokens
HyperFrames GSAP composition lint rules and animation patterns for short-form video
javascript hyperframes gsap tiktok video-rendering 494 tokens