Class PerformanceOptimizer

src/js/performance.js:2–327

// 性能优化模块
class PerformanceOptimizer {
  constructor() {
    this.isOnline = navigator.onLine;
    this.observers = new Map(); // Track observers for cleanup
    this._webpSupported = null; // 缓存 WebP 检测结果
    this._parallaxElements = null; // 缓存视差元素查询
    this.init();
  }

  init() {
    this.setupNetworkListeners();
    this.optimizeImages();
    this.setupScrollOptimization();
    this.setupIntersectionObserver();
    this.setupTouchOptimization();
    this.setupVisibilityHandler();
  }

  // Cleanup method to prevent memory leaks
  destroy() {
    // Clean up all observers
    this.observers.forEach((observer, key) => {
      observer.disconnect();
    });
    this.observers.clear();
  }

  // （Service Worker 已停用）

  // 设置网络监听器
  setupNetworkListeners() {
    window.addEventListener('online', () => {
      this.isOnline = true;
      this.showNetworkStatus('网络已连接', 'success');
    });

    window.addEventListener('offline', () => {
      this.isOnline = false;
      this.showNetworkStatus('网络已断开，使用离线模式', 'warning');
    });
  }

  // 显示网络状态
  showNetworkStatus(message, type) {
    const toast = document.createElement('div');
    toast.className = `network-status ${type} fade-in`;
    toast.textContent = message;

    document.body.appendChild(toast);

    setTimeout(() => {
      toast.classList.add('fade-out');
      setTimeout(() => toast.remove(), 300);
    }, 3000);
  }

  // 图片优化
  optimizeImages() {
    const images = document.querySelectorAll('img[data-src]');