TypeError：无法读取Cloud Firestore中未定义的属性“ uid”

Question

使用云功能更新文档时如何获取身份验证ID /用户ID

当前我遇到以下错误

TypeError: Cannot read property 'uid' of undefined
    at exports.updateUser.functions.firestore.document.onUpdate (/srv/lib/index.js:19:28)
    at cloudFunctionNewSignature (/srv/node_modules/firebase-functions/lib/cloud-functions.js:120:23)
    at /worker/worker.js:825:24
    at <anonymous>
    at process._tickDomainCallback (internal/process/next_tick.js:229:7)

代码：

export const updateUser = functions.firestore.document("user/{userid}/userProfile/{documentid}").onUpdate((change, context) => {

   const latestValue : FirebaseFirestore.DocumentData | any = change.after.data()

   const usersCount: number  = latestValue.followers

   if(usersCount == 2)
   {


         const tempDocu = {
            current: true,
            lastPost:admin.firestore.FieldValue.serverTimestamp(),
            recentPosts:admin.firestore.FieldValue.arrayUnion(null),
            users:admin.firestore.FieldValue.arrayUnion(null)
         }

         const auth  = context.params.uid

        return admin.firestore().collection("followers/ "+ auth+"/recentPostColl").doc().create(tempDocu)

   }

   return null
})

文档生成为undefined