Code Quiz

Deferring Work Off the Launch Path

Spot why this 'deferred' analytics init still hurts app launch time and TTI.

Codejavascript

// index.js — app entry point
import { AppRegistry, InteractionManager } from 'react-native';
import App from './App';
import { name as appName } from './app.json';
import { initAnalytics, initCrashReporting, warmImageCache } from './startup';

// Move non-critical setup off the launch path so the UI paints first
InteractionManager.runAfterInteractions(() => {
  initAnalytics();
  initCrashReporting();
});

// Prewarm caches before the first frame
warmImageCache();

AppRegistry.registerComponent(appName, () => App);

The team wanted heavy startup work deferred so the first screen renders fast, but TTI barely improved. What is the bug?

Next →Optimizing Launch Time and TTI