前端封装 IndexedDB 存储和使用gltf模型文件的方法，以重复使用代码

class IndexedDBManager {
  constructor() {
    this.dbName = 'GltfModelCache';
    this.dbVersion = 1;
    this.storeName = 'gltfModels';
  }
 
  // 打开或创建IndexedDB
  openDB() {
    return new Promise((resolve, reject) => {
      const request = window.indexedDB.open(this.dbName, this.dbVersion);
 
      request.onerror = (event) => {
        console.error('Database error: ', event.target.errorCode);
        reject(event.target.errorCode);
      };
 
      request.onsuccess = (event) => {
        this.db = event.target.result;
        resolve();
      };
 
      request.onupgradeneeded = (event) => {
        const db = event.target.result;
        if (!db.objectStoreNames.contains(this.storeName)) {
          db.createObjectStore(this.storeName, { keyPath: 'url' });
        }
      };
    });
  }
 
  // 将gltf模型存储到IndexedDB
  saveGltfModel(url, arrayBuffer) {
    return this.openDB().then(() => {
      const transaction = this.db.transaction([this.storeName], 'readwrite');
      const store = transaction.objectStore(this.storeName);
      const request = store.put({ url, arrayBuffer });
 
      return new Promise((resolve, reject) => {
        request.onsuccess = () => resolve();
        request.onerror = () => reject(request.error);
      });
    });
  }
 
  // 从IndexedDB获取gltf模型
  getGltfModel(url) {
    return this.openDB().then(() => {
      const transaction = this.db.transaction([this.storeName]);
      const store = transaction.objectStore(this.storeName);
      const request = store.get(url);
 
      return new Promise((resolve, reject) => {
        request.onsuccess = (event) => {
          const gltfModel = event.target.result;
          if (gltfModel) {
            resolve(gltfModel.arrayBuffer);
          } else {
            reject('Model not found');
          }
        };
        request.onerror = () => reject(request.error);