A JSON File 19% Smaller That Ships Only 3% Smaller — Measuring Catalog Payloads Against gzip
Five payload formats measured on a 20,000-item wallpaper catalog. Key shortening saves just 3.2% after gzip, while a columnar layout cuts 26.8%. Real numbers for Brotli, paging, and JSON.parse time.
When Two-Character Queries Silently Return Nothing: Measuring Japanese Search Indexes in an Expo App
SQLite FTS5's trigram tokenizer returns zero rows for Japanese queries shorter than three characters, without raising anything. I benchmarked linear scan, a bigram inverted index, and FTS5 over a 20,000-item catalog to find the real threshold.
Collapsing Duplicate Requests Into One: A Reference-Counted Single-Flight Layer
When several components fire the same API call at launch, you get a burst of identical requests. Here is a single-flight layer that shares one in-flight promise instead: how to build the key that decides the folding, the trap of handing out a failed promise forever, the trap of one caller's abort cancelling everyone, and the test that keeps it all from regressing, with the real network numbers alongside.
Adding React Compiler to Expo Let Me Delete 41 Hand-Written memo Calls
I enabled React Compiler on Rork-generated React Native screens and measured the rerender counts with Profiler. Here is how I decided which memo and useCallback calls were safe to delete, how to find the components the compiler bailed out on, and how to catch regressions in CI.
Migrating Rork Max SwiftUI to @Observable: Narrowing the Re-renders ObservableObject Was Spreading
Rork Max tends to generate SwiftUI apps built on ObservableObject and @Published, where a single state change re-evaluates every subscribing view. Moving to the Observation framework's @Observable narrows invalidation to the property level. Here is the migration path, plus the view-body execution counts I measured in Instruments before and after.
When a New Architecture Migration Only Janks in Release Builds — Field Notes on Catching Silent Interop-Layer Fallback
A Rork app on the New Architecture scrolled fine in development but stuttered only in release builds on real devices. The cause: a legacy native module quietly falling back to the interop layer. Field notes on measuring it and rolling out a fix without reverting the whole app.
When Your App's Launch Got Quietly Slower Release After Release — Field Notes on TTI Instrumentation and a Startup Budget for Rork Apps
Rork apps tend to start fast on day one, then drift slower as you add features and SDKs. These field notes show how to catch cold-start regressions that averages hide, trace them to a release, and stop the drift with a CI startup budget.
Your Animation Keeps Running After You Leave the Screen — Focus-Aware Battery Savings in a Rork (Expo) App
In a Rork-generated Expo app, a gradient or breathing animation can keep running after you push another screen or background the app, quietly draining the battery without ever surfacing as jank. The cause is that Reanimated's withRepeat lives on the UI thread and the navigation stack keeps screens mounted. This shows a lifecycle design — useIsFocused plus AppState — that reliably stops off-screen and background loops, with working code.
When an Image-Heavy Rork App Quietly Bloats Its Cache and Dies on Memory — Field Notes on Measuring and Capping
In a Rork app where images are the product, expo-image's disk cache and resident memory creep up over a session and surface as OOM crashes. Here's how I measured the bloat, where I set caps, and what I trimmed on the delivery side — with working code, in the order that actually helped.
Fixing Stutter When a Rork Max SwiftUI Image Grid Scrolls
Measure why a Rork Max SwiftUI image grid stutters while scrolling, then fix it with ImageIO downsampling, off-main-thread decoding, and stable cells to cut real-device hitches.
Quietly Dialing Back Heavy Work When the Device Gets Hot or Enters Low Power Mode
How to watch ProcessInfo's thermalState and Low Power Mode and degrade heavy work in stages when the device is hot or the battery is low, with working Swift code.
When Rork-Built Lists Stutter: Designing Image Caching and Prefetch
A FlatList from Rork starts stuttering once the images pile up. Here is how I restore smoothness with expo-image caching, recyclingKey, prefetch, and a move to FlashList, with the device numbers I measured.