text: /**
   * Storage封装
   */
  const STORAGE_KEY = 'mall';
  
  export default {
  
      // 存储值
      setItem(key, value, module_name) {
          if (module_name) {
              let val = this.getItem(module_name);
              val[key] = value;
              this.setItem(module_name, val);
          } else {
              let val = this.getStorage();
              val[key] = value;
              window.sessionStorage.setItem(STORAGE_KEY, JSON.stringify(val));
          }
      },
      // 获取某一个模块下面的属性user下面的userName
      getItem(key, module_name) {
          if (module_name) {
              let val = this.getItem(module_name);
              if (val) return val[key];
          }
          return this.getStorage()[key];
      },
      getStorage() {
          return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY || '{}'));
      },
      clear(key, module_name) {
          let val = this.getStorage();
          if (module_name) {
              if (!val[module_name]) return;
              delete val[module_name][key];
          } else {
              delete val[key];
          }
          window.sessionStorage.setItem(STORAGE_KEY, JSON.stringify(val));
      }
  }