import createApp from './create-app'export default context => {  return new Promise((resolve, reject) => {   //异步操作，让server-render知道什么时候结束    const {app, router} = createApp()    router.push(context.url)       //**入口**//在服务端，给路由推一条记录，匹配到要调用的组件    router.onReady(() => {      const matchedComponents = router.getMatchedComponents()//根据url匹配到组件，再做些操作      if (!matchedComponents.length) {        return reject(new Error('no component matched'))      }      context.meta = app.$meta()  //vue-meta知识      resolve(app)    })  })}复制代码