Redux selectors help your app efficiently read data from the store. They reduce unnecessary re-renders by returning cached results when data hasn't changed. This keeps your UI smooth, aiming for 60 frames per second, which feels natural and responsive on mobile devices.
Without selectors, your app might re-render too often, wasting CPU and battery. Selectors also help keep memory use low by avoiding duplicate data copies.
Use memoized selectors (like those created with reselect) to cache results and avoid recalculations. This means your app only updates components when the relevant data changes.
Keep selectors simple and focused on small slices of state. Avoid heavy computations inside selectors; if needed, move complex logic outside or use asynchronous data fetching.
Test your selectors with React DevTools and Redux DevTools to ensure components only re-render when necessary.
Adding selectors, especially memoized ones, adds minimal size to your app bundle—usually just a few kilobytes from libraries like reselect. This has a negligible effect on startup time.
Well-structured selectors can improve perceived startup speed by reducing unnecessary renders during initial load.
Redux selectors work the same on both iOS and Android in React Native apps. However, performance differences may arise from platform-specific JavaScript engine optimizations.
On iOS, JavaScriptCore is used, while Android uses Hermes or V8. Hermes is optimized for React Native and can improve selector performance and memory use.
Ensure your selectors are efficient to benefit both platforms equally and test on real devices to catch platform-specific issues.
Using Redux selectors does not directly affect app store guidelines. However, efficient state management helps your app stay responsive and stable, which aligns with Apple's Human Interface Guidelines and Google Play's quality requirements.
Ensure your app does not freeze or crash due to inefficient state updates, as this can cause rejection during review.
Keep your app's memory use reasonable; excessive memory from poor state handling can lead to app termination by the OS.
It's likely your selectors are not memoized, causing repeated heavy calculations and unnecessary re-renders. This slows down rendering and delays screen load.
Another cause could be selectors reading large or deeply nested state without optimization, increasing CPU and memory use.
Check if your selectors use reselect or similar memoization and simplify state shape if needed.