code: function addExtension(type, extension) {
      if (!extension) {
          return;
      }
  
      let cache = pluginCache;
      if (process.env.APP_TYPE === 'quick') {
          cache = appGlobal.okamPluginCache;
      }
  
      let existedExtensions = cache.usedExtensions[type];
      /* istanbul ignore next */
      if (!existedExtensions) {
          existedExtensions = cache.usedExtensions[type] = [];
      }
  
      existedExtensions.push(extension);
  }
docs: Add extension
  
  @inner
  @param {string} type the extension type
  @param {Object} extension the extension