如何提升React Native移动应用运行速度？我的v0.40.0版本应用点击卡顿

Hey there, let's break down why your React Native 0.40.0 app is lagging on every tap—this version is pretty dated (circa 2017), so there's a mix of framework quirks and outdated dependency issues at play. Here are actionable steps to fix this:

React Native 0.40.0 has critical performance gaps that were fixed in later versions, especially around touch event handling and JS thread scheduling. This is the biggest win you can get:

• Use react-native-git-upgrade (the official upgrade tool for older versions) to move to a more recent stable release (aim for 0.50+ at minimum, though even that's old—0.60+ would be better if your dependencies can support it).
• Note: You'll need to audit your dependencies for compatibility during the upgrade, but the performance payoff is worth the effort.

Looking at your dependency list, several packages are running very old versions that could be blocking the JS thread:

• analytics-react-native@1.1.0: Old analytics libraries often run heavy sync operations (like logging or network calls) directly in tap handlers. Try temporarily disabling it—if taps feel faster, upgrade to the latest version compatible with RN 0.40, or wrap its calls in InteractionManager.runAfterInteractions() to avoid blocking UI.
• lodash & lodash.range: Avoid calling _.range or other lodash methods directly in your render() function—this creates new arrays on every render, triggering unnecessary re-renders. Cache these values in your component's constructor or componentWillMount instead.
• immutable@3.8.1: Double-check that you're using immutable state correctly. Accidental deep copies or unnecessary state updates can force entire component trees to re-render, slowing down taps. Use Immutable.is() in shouldComponentUpdate to skip unnecessary renders.

Tap delays almost always happen when the JS thread is tied up. Here's how to diagnose and fix it:

• Enable the Perf Monitor from the React Native dev menu—if your JS thread frame rate drops below 60fps during taps, you've got a blocking issue.
• Use Debug JS Remotely with Chrome's Performance tab: Record a tap action, then look for long-running functions (anything over 16ms) that are hogging the thread. Common culprits include sync network calls, heavy calculations, or large state updates in tap handlers.
• Move heavy work out of tap handlers with InteractionManager:

  onPress={() => {
    // Update UI immediately (e.g., disable button)
    this.setState({ isLoading: true });
    // Run heavy tasks after the UI has finished updating
    InteractionManager.runAfterInteractions(() => {
      this.fetchData();
      this.logAnalytics();
    });
  }}
  

React 15.4.2 (which your app uses) lacks modern hooks like useMemo/useCallback, so you'll need manual optimizations:

• Add shouldComponentUpdate to frequently rendered components (like list items) to skip re-renders when props/state haven't changed:

  shouldComponentUpdate(nextProps, nextState) {
    return !Immutable.is(this.props, nextProps) || !Immutable.is(this.state, nextState);
  }
  

• Avoid defining functions directly in render() (e.g., onPress={() => {...}}). Instead, bind functions in the constructor to prevent new function references on every render:

  constructor(props) {
    super(props);
    this.handleTap = this.handleTap.bind(this);
  }
  
  handleTap() {
    // Your tap logic here
  }
  
  render() {
    return <TouchableOpacity onPress={this.handleTap} />;
  }
  

Some third-party native modules can block the main thread in older RN versions:

• Temporarily remove modules like geolib or analytics-react-native one by one—if taps speed up after removing a module, that's the culprit. Look for updated versions or alternative packages that play nicer with RN 0.40.
• Ensure apisauce requests are asynchronous—never make sync network calls in tap handlers, as they'll freeze the JS thread.

• Disable Debug Mode: Debug JS Remotely cripples performance—always test tap speed in Release mode (react-native run-android --variant=release or react-native run-ios --configuration Release).
• Clear Cache: Run react-native start --reset-cache to eliminate stale build artifacts that might be causing unexpected slowdowns.

内容的提问来源于stack exchange，提问作者Kishan Vaghela