https://rgndunes.github.io Working notebook of Divyansh Singh — Software Engineer II at Rippling, building frontend infrastructure, developer tooling, and CI/CD systems. en Thu, 15 Oct 2026 05:37:20 GMT rgndunes@gmail.com (Divyansh Singh) rgndunes@gmail.com (Divyansh Singh) Software Engineering Web Development https://rgndunes.github.io/og-default.png https://rgndunes.github.io 144 144 https://rgndunes.github.io/blog/vite-dev-bottleneck-was-eager-route-imports https://rgndunes.github.io/blog/vite-dev-bottleneck-was-eager-route-imports Thu, 15 Oct 2026 00:00:00 GMT A local Vite page took 90 seconds to load because eager route imports pulled 11,516 modules into one page load. Making routes lazy cut it to 54 modules and 10.54 seconds. The mechanism, how to count your own modules, and where the fix stops working. ViteFrontend InfrastructureDeveloper ExperiencePerformanceReact https://rgndunes.github.io/blog/claude-edited-500gb-raw-footage-4k-film https://rgndunes.github.io/blog/claude-edited-500gb-raw-footage-4k-film Wed, 14 Oct 2026 00:00:00 GMT A practical AI-assisted editing case study for first-time creators and experienced editors: 500 GB of footage, three rebuilds, custom cleanup, 3D maps and a finished 4K film. AI EngineeringVideo ProductionAgentic WorkflowsClaudeAutomation https://rgndunes.github.io/blog/every-browser-retry-you-add-is-a-small-ddos-attack-stop-calling-it-reliability https://rgndunes.github.io/blog/every-browser-retry-you-add-is-a-small-ddos-attack-stop-calling-it-reliability Tue, 13 Oct 2026 00:00:00 GMT Retries keep a single request alive, but at production scale they can turn an outage into a traffic multiplier. The browser needs a retry policy, not a setTimeout loop. Frontend ReliabilityWeb PerformanceHTTPJavaScriptArchitecture https://rgndunes.github.io/blog/lazy-hero-image-waits-for-your-css https://rgndunes.github.io/blog/lazy-hero-image-waits-for-your-css Tue, 13 Oct 2026 00:00:00 GMT loading="lazy" on an above-the-fold image does not wait for a scroll, it waits for layout. Measured in Chromium, Firefox and WebKit: the lazy hero request starts right after the stylesheet lands, costing 16ms on one network profile and 428ms on another, why fetchpriority cannot rescue it, and why making everything eager is worse. Web PerformanceLCPBrowser InternalsImagesFrontend Infrastructure https://rgndunes.github.io/blog/settimeout-zero-is-not-zero https://rgndunes.github.io/blog/settimeout-zero-is-not-zero Thu, 08 Oct 2026 00:00:00 GMT The delay you pass to setTimeout is a minimum. Measured in Chromium, Firefox, WebKit and Node: the 4ms nesting clamp, hidden tabs throttled to 1 second, Chrome's once-a-minute intensive throttling after 5 minutes, a 30-day timer that fires instantly, and what to use instead. JavaScriptBrowser InternalsPerformanceTimersFrontend Infrastructure https://rgndunes.github.io/blog/javascript-date-parsing-off-by-one https://rgndunes.github.io/blog/javascript-date-parsing-off-by-one Tue, 06 Oct 2026 00:00:00 GMT new Date("2026-10-06") is UTC midnight, new Date("2026-10-06T00:00") is local midnight. Tested in Chromium, Firefox and WebKit across three time zones: where the day slips, why Indian teams rarely see it, "06-10-2026" becoming 10 June, DST arithmetic, and what Temporal fixes. JavaScriptBrowser InternalsTemporalDatesFrontend Infrastructure https://rgndunes.github.io/blog/chrome-stopped-running-your-unload-handler https://rgndunes.github.io/blog/chrome-stopped-running-your-unload-handler Thu, 01 Oct 2026 00:00:00 GMT Since Chrome 154, unload handlers are off by default on every Chrome page load - they register without error and never run. Reproduced in Chromium: what it does to the Back button, which data quietly went missing during the seven-month rollout, and the pagehide pattern to use instead. Browser InternalsPerformancePage LifecycleAnalyticsFrontend Infrastructure https://rgndunes.github.io/blog/cache-control-no-cache-does-not-mean-do-not-cache https://rgndunes.github.io/blog/cache-control-no-cache-does-not-mean-do-not-cache Thu, 24 Sep 2026 00:00:00 GMT no-cache stores the response and revalidates it every time - no-store is the one that refuses to store. And an index.html with no Cache-Control at all is still cached, for a period the browser works out from Last-Modified. Reproduced in Chromium, with the two-rule setup I would use. HTTP CachingFrontend InfrastructurePerformanceRelease EngineeringCDN https://rgndunes.github.io/blog/service-worker-is-a-deploy-you-cannot-roll-back https://rgndunes.github.io/blog/service-worker-is-a-deploy-you-cannot-roll-back Tue, 22 Sep 2026 00:00:00 GMT Once a service worker is installed, the browser decides when your new release runs, and rollback cannot reach it. Why reloading does not activate a new worker, how skipWaiting breaks lazy chunks in open tabs, and the kill switch to write before you need it. Service WorkersPWAFrontend InfrastructureRelease EngineeringJavaScript https://rgndunes.github.io/blog/client-env-prefix-is-a-publish-button https://rgndunes.github.io/blog/client-env-prefix-is-a-publish-button Thu, 17 Sep 2026 00:00:00 GMT Renaming a variable so it stops being undefined pastes its value into a public JavaScript file. What client env prefixes really do at build time, the dynamic lookup that inlines every prefixed variable in Vite, the define config that leaked a whole shell environment, and a CI check that catches it. ViteNext.jsSecurityFrontend InfrastructureBuild Tools https://rgndunes.github.io/blog/package-json-exports-is-a-breaking-change https://rgndunes.github.io/blog/package-json-exports-is-a-breaking-change Wed, 16 Sep 2026 00:00:00 GMT Six lines of JSON can make every deep import your consumers rely on throw at runtime, including require('pkg/package.json'). How the exports field really resolves, the TypeScript condition-order bug that fails silently, the dual package hazard, and how to roll it out without breaking anyone. npmNode.jsTypeScriptFrontend InfrastructurePackage Design https://rgndunes.github.io/blog/long-animation-frames-not-long-tasks https://rgndunes.github.io/blog/long-animation-frames-not-long-tasks Thu, 27 Aug 2026 00:00:00 GMT The Long Tasks API tells you that something blocked the main thread for 340ms. It will not tell you which script, which handler, or which line. Long Animation Frames does - and it measures the unit users actually perceive, which is the frame, not the task. PerformanceBrowser APIsObservabilityINPCore Web Vitals https://rgndunes.github.io/blog/your-ci-cache-is-a-second-package-manager-treat-it-like-one https://rgndunes.github.io/blog/your-ci-cache-is-a-second-package-manager-treat-it-like-one Tue, 25 Aug 2026 00:00:00 GMT A CI cache can cut minutes from a build, or quietly make your release process non-reproducible. The difference is whether you treat it as disposable acceleration or hidden infrastructure. CI/CDBuild SystemsFrontend InfrastructureDeveloper Experiencenpm https://rgndunes.github.io/blog/ci-stop-running-every-test https://rgndunes.github.io/blog/ci-stop-running-every-test Thu, 20 Aug 2026 00:00:00 GMT Most teams run the full test suite on every PR and call it thorough. It is not thorough - it is expensive, slow, and quietly teaches everyone to distrust the results. Change-based test selection is a decade old. Frontend teams are still running 40 minutes of tests to validate a one-line change. CITest SelectionFrontend Infrastructure https://rgndunes.github.io/blog/node-libuv-thread-pool-of-four https://rgndunes.github.io/blog/node-libuv-thread-pool-of-four Tue, 18 Aug 2026 00:00:00 GMT Every 'JavaScript is single-threaded' explanation forgets that Node.js is not single-threaded. It runs on libuv, which spins up a fixed thread pool of four workers by default. crypto, fs, dns.lookup, zlib - they all queue on those four. Node.jslibuvBackend https://rgndunes.github.io/blog/react-key-is-a-reset-button https://rgndunes.github.io/blog/react-key-is-a-reset-button Thu, 13 Aug 2026 00:00:00 GMT Every React tutorial teaches keys the same way - 'they help React tell items apart in a list'. That framing is why production React code is full of stale state, ghost animations, and forms that remember the last user's input. key is a reset primitive, not an identity marker. ReactReconciliationFrontend Internals https://rgndunes.github.io/blog/what-is-ci-what-is-cd https://rgndunes.github.io/blog/what-is-ci-what-is-cd Tue, 11 Aug 2026 00:00:00 GMT Everyone says CI/CD. Almost nobody can cleanly define the two letters or draw the line between them. A definitions-first walkthrough: what CI is, what CD is, why there are actually two CDs, and where one ends and the other begins. CI/CDDevOpsFrontend Infrastructure https://rgndunes.github.io/blog/devtools-breakpoints-v8-inspector-protocol https://rgndunes.github.io/blog/devtools-breakpoints-v8-inspector-protocol Thu, 06 Aug 2026 00:00:00 GMT You hit F8 and time stops. Every variable frozen. But how does DevTools actually pause a running JavaScript engine? The answer is a WebSocket, a bespoke protocol from Chrome, and a debugger statement that is not what you think it is. Browser InternalsV8DevTools https://rgndunes.github.io/blog/ai-model-paralysis https://rgndunes.github.io/blog/ai-model-paralysis Mon, 20 Jul 2026 00:00:00 GMT When your org gives you access to Claude, Gemini, ChatGPT, and a dozen others - each with different models, effort levels, and credit caps - how do you decide? A framework for choosing AI models that maximises accuracy without burning through your budget. AI ToolsDeveloper ExperienceDecision Frameworks https://rgndunes.github.io/blog/i-stopped-using-npm-install-heres-the-40-second-trick-that-changed-how-i-debug-dependencies https://rgndunes.github.io/blog/i-stopped-using-npm-install-heres-the-40-second-trick-that-changed-how-i-debug-dependencies Sat, 11 Jul 2026 00:00:00 GMT Most engineers reinstall node_modules when debugging dependency issues. There's a faster way that lets you patch, test, and iterate on third-party packages in seconds - without waiting for CI or publishing to a test registry. Frontend InfrastructurenpmDeveloper Experience https://rgndunes.github.io/blog/ai-token-limits-pxpipe-solution https://rgndunes.github.io/blog/ai-token-limits-pxpipe-solution Fri, 10 Jul 2026 00:00:00 GMT How one developer's frustration with Claude's token costs led to discovering pxpipe - a tool that packs 18 million characters into a 1M token window by converting text to images. AI ToolingCost OptimisationClaudeDeveloper ToolsPerformance https://rgndunes.github.io/blog/react-server-components-data-leak https://rgndunes.github.io/blog/react-server-components-data-leak Fri, 10 Jul 2026 00:00:00 GMT Why the server/client boundary in React Server Components is a security minefield that most teams are crossing blindly - and how serialisation turns your careful access control into a data exposure incident waiting to happen. ReactSecurityServer ComponentsNext.jsArchitecture https://rgndunes.github.io/blog/your-rust-build-tool-is-slower-than-webpack https://rgndunes.github.io/blog/your-rust-build-tool-is-slower-than-webpack Tue, 07 Jul 2026 00:00:00 GMT Turbopack, SWC, and esbuild promise instant builds. But in real-world monorepos with warm caches and incremental compilation, Webpack still wins. Here's the nuanced truth about build tool performance that benchmark charts don't show. Build ToolsWebpackRustPerformanceDeveloper Experience https://rgndunes.github.io/blog/prompting-vs-looping-in-ai https://rgndunes.github.io/blog/prompting-vs-looping-in-ai Sun, 28 Jun 2026 00:00:00 GMT The difference between prompting and looping in AI models like Claude isn't about cost - it's about control. Here's what every engineer building with LLMs needs to know about determinism, context retention, and when to let the model think versus when to take control. AI EngineeringLLMArchitectureProduction Patterns https://rgndunes.github.io/blog/tree-shaking-is-a-lie https://rgndunes.github.io/blog/tree-shaking-is-a-lie Tue, 23 Jun 2026 00:00:00 GMT The frontend community sold you on tree shaking as the silver bullet for bundle size. But your production bundles are still bloated with unused code. Here's why the promise was always incomplete - and what actually works. Build SystemsPerformanceWebpackRollupViteesbuild https://rgndunes.github.io/blog/react-useeffect-memory-leaks https://rgndunes.github.io/blog/react-useeffect-memory-leaks Mon, 08 Jun 2026 00:00:00 GMT After reviewing over 40 production React codebases, the pattern is impossible to ignore: useEffect-related memory leaks are everywhere. Here is what every team is getting wrong, and how to audit your own code before users start noticing. ReactMemory LeaksPerformanceJavaScriptFrontend Engineering https://rgndunes.github.io/blog/source-maps-security-vulnerability https://rgndunes.github.io/blog/source-maps-security-vulnerability Wed, 03 Jun 2026 00:00:00 GMT Most frontend teams ship source maps to production without realising they're handing anyone a complete, readable copy of their application code. Here's what's actually inside them, how they get exploited, and what to do about it today. SecurityBuild SystemsFrontend InfrastructurewebpackVite https://rgndunes.github.io/blog/vibe-coding-technical-debt-report https://rgndunes.github.io/blog/vibe-coding-technical-debt-report Tue, 02 Jun 2026 00:00:00 GMT We shipped more features in 12 months than in the previous three years combined. We also quietly built the most confusing codebase of my career. Here is the honest audit. AITechnical DebtProduction EngineeringFrontend https://rgndunes.github.io/blog/hydration-is-the-most-expensive-lie-in-frontend https://rgndunes.github.io/blog/hydration-is-the-most-expensive-lie-in-frontend Tue, 26 May 2026 00:00:00 GMT Hydration makes your browser rebuild the entire page a second time just to make it interactive. Here is what it actually costs, and how islands, resumability, and Server Components are quietly replacing it. HydrationReactPerformanceFrontend ArchitectureWeb Performance https://rgndunes.github.io/blog/replaced-npm-with-browser-apis https://rgndunes.github.io/blog/replaced-npm-with-browser-apis Thu, 21 May 2026 00:00:00 GMT How I audited our production app's dependency tree, replaced a dozen packages with native browser APIs, and cut our bundle by 58%. A practical guide to the platform features hiding in plain sight. FrontendDependenciesBrowser APIsPerformance