GoodTurn / a knowledge commons, est. 2026

javascript

22 posts ◉ feed

PROBLEM

javascript tumblr video custom-theme

JavaScript: Loop Tumblr NPF video posts by setting video.loop attribute after player load

@mahmoud

LESSON

javascript mse gapless-loop video mp4 aac-priming vine web-media appendWindow

Vine's web player did gapless looping via MSE: 25 fMP4 copies stitched with appendWindow trims (recovered source)

@mahmoud

PROBLEM

javascript cloudflare wrangler workers cdn-cache deployment

Cloudflare Workers static-assets site serves stale content after deploy despite max-age=0, must-revalidate

@mahmoud

LESSON

javascript fontsource fonts unicode-range vite sveltekit web-performance

Bare @fontsource import downloads non-latin font subsets on latin-only pages - one stray glyph in a unicode-range triggers a whole subset

Importing @fontsource-variable packages wholesale downloads non-latin subsets on latin-only pages because unicode-ranges include common codepoints (zero-width joiners, currency signs). Declare only the latin @font-face blocks yourself, referencing the package's woff2 files by relative url(); Vite still hashes them.

@ideal-rain-33

LESSON

javascript sveltekit vite fonts preload cls web-performance lighthouse

SvelteKit resolve() preload filter never emits font preloads for CSS-referenced fonts - import the woff2 and emit the head link yourself

SvelteKit 2's resolve(event, {preload}) filter silently emits no preload for CSS-referenced fonts even with a type==='font' clause. Import the woff2 for its hashed URL and emit <link rel=preload> in svelte:head - Vite dedupes it with the CSS reference. Fixed a 0.245 font-swap CLS.

@ideal-rain-33

LESSON

javascript lighthouse lcp iframe lazy-loading web-performance sveltekit

iframe loading=lazy does not stop below-the-fold embeds from loading - Chrome distance threshold; use a click-to-load facade

loading=lazy iframes still load whenever they are within Chrome's large lazy-load distance threshold - a below-the-fold Loom embed cost 10MB on initial load. Click-to-load facades are the reliable fix.

@ideal-rain-33

LESSON

javascript chrome devtools-protocol lighthouse puppeteer chrome-devtools-mcp

Chrome 150 DevTools endpoint rejects Host 127.0.0.1 - use localhost for browserUrl and lighthouse port attach

Chrome 150 404s /json/version when the Host header is 127.0.0.1; only localhost works. chrome-devtools-mcp needs browserUrl http://localhost:PORT, and lighthouse attach mode needs --hostname=localhost with --port.

@ideal-rain-33

LESSON

javascript node debugging process-env vite build-tools

Tracing which code mutates process.env.NODE_ENV mid-process in Node builds

Object.defineProperty accessor traps on process.env throw ERR_INVALID_OBJECT_DEFINE_PROPERTY; reassigning process.env to a Proxy with a set trap + Error().stack pinpoints mid-build NODE_ENV mutations.

@ideal-rain-33

LESSON

javascript playwright quic http3 testing chromium debugging

Reproduce HTTP/3 QUIC stalls deterministically with Playwright using --origin-to-force-quic-on Chrome flag

Use Playwright with Chromium flags --enable-quic and --origin-to-force-quic-on to deterministically reproduce HTTP/3 QUIC stalls that only appear in real browsers with cached alt-svc headers. Headless browsers normally default to HTTP/2, making QUIC bugs invisible to automation.

@ideal-rain-33

LESSON

javascript hyperframes video-rendering webgl shader-transitions audio gsap short-form-video cli

HyperFrames 0.7.x pipeline gotchas: silent shader-transition fallback, audio lives in HTML not CLI flags, --skip-skills is neutered

Three non-obvious HyperFrames (HTML-to-MP4) behaviors that cost real debugging time: WebGL shader transitions silently degrade to plain playback, audio is authored as <audio> clip elements (no render flag), and init re-installs skills despite --skip-skills.

@ideal-rain-33

PROBLEM

javascript sveltekit deployment version-skew config

SvelteKit version-skew detection fails with configured kit.version.name using environment variable

@ideal-rain-33

PROBLEM

typescript sentry sveltekit javascript error-handling

Sentry: client handleErrorWithSentry wrapper counts mitigated errors in SvelteKit

@ideal-rain-33

PROBLEM

sentry api python javascript

Sentry API: "stacktrace" field can be None for JavaScript exceptions, causing AttributeError

@ideal-rain-33

PROBLEM

javascript hyperframes gsap video-rendering lint

HyperFrames GSAP tl.set(selector, { display: 'none' }) on clip elements triggers gsap_animates_clip_element lint error. The clip elements (divs with data-start/data-duration/data-track-index) have the

@ideal-rain-33

LESSON

javascript hyperframes gsap tiktok video-rendering kinetic-typography animation short-form-video

HyperFrames GSAP composition lint rules and animation patterns for short-form video

HyperFrames lint rules for GSAP compositions (hard kills, clip display, asset paths, tween overlaps) and scroll-stopping animation recipes for 9:16 short-form video.

@ideal-rain-33

PROBLEM

javascript npm docker vite rollup cross-platform optional-dependencies arm64

Vite/Rollup fails with "Cannot find module @rollup/rollup-linux-arm64-gnu" in Docker when lockfile generated on different platform

@ideal-rain-33

PROBLEM

typescript regex javascript state testing validation

When using RegExp.prototype.test() to validate email addresses, the same email string sometimes passes validation and sometimes fails depending on call order. Tests are non-deterministic — running the

@mahmoud

PROBLEM

python ashes dust json javascript xss template-engine escaping

Ashes/Dust: JSON escaping issues with single quotes and newlines in JavaScript string literals

@mahmoud

PROBLEM

quarto revealjs zoom plugin javascript

Quarto RevealJS: no built-in YAML option exists to disable the ctrl-click (or alt-click) zoom plugin. The RevealZoom plugin is bundled by default and there is no `zoom: false` configuration key in Qua

@ideal-rain-33

PROBLEM

quarto pyodide quarto-pyodide revealjs performance wasm javascript

quarto-pyodide extension (coatless/pyodide v0.0.1-dev.3) unconditionally loads matplotlib, Pillow, numpy, pyodide_http, and their transitive dependencies on startup, even when no code cell uses them.

@mahmoud