使用firebase函数删除firestore集合

我试图设置一个firebase函数,在删除文档时删除文档的所有子集合。 通过阅读文档,我得出了以下代码:

// The Cloud Functions for Firebase SDK to create Cloud Functions and setup triggers.
const functions = require('firebase-functions');



// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
// exports.helloWorld = functions.https.onRequest((request, response) => {
//  response.send("Hello from Firebase!");
// });

exports.DeleteColletionFunction = functions.firestore
    .document('exampleCollection/{exampleID}')
    .onDelete((snap, context) => {
        // Get an object representing the document prior to deletion
      // e.g. {'name': 'Marie', 'age': 66}
      const deletedValue = snap.data();
      deleteCollection()


    });



function deleteCollection(db, collectionPath, batchSize) {
    var collectionRef = db.collection(collectionPath);
    var query = collectionRef.orderBy('__name__').limit(batchSize);

    return new Promise((resolve, reject) => {
      deleteQueryBatch(db, query, batchSize, resolve, reject);
    });
  }

  function deleteQueryBatch(db, query, batchSize, resolve, reject) {
    query.get()
        .then((snapshot) => {
          // When there are no documents left, we are done
          if (snapshot.size == 0) {
            return 0;
          }

          // Delete documents in a batch
          var batch = db.batch();
          snapshot.docs.forEach((doc) => {
            batch.delete(doc.ref);
          });

          return batch.commit().then(() => {
            return snapshot.size;
          });
        }).then((numDeleted) => {
          if (numDeleted === 0) {
            resolve();
            return;
          }

          // Recurse on the next process tick, to avoid
          // exploding the stack.
          process.nextTick(() => {
            deleteQueryBatch(db, query, batchSize, resolve, reject);
          });
        })
        .catch(reject);
  }

我以前从未使用过云功能,因此不确定下一步该做什么。我看到为了使用delete collection函数,必须传递一个数据库、collectionpath和batchsize。在这种情况下,要传递的正确值是什么?

我应该使用这行代码来获取firestore数据库吗?

const database = admin.firestore();

从文档中复制此函数时,我也会遇到一些错误:

应为“==”,而不是看到“==”

[埃斯林特]避免背弃承诺。(承诺/不筑巢) (参数)快照:任意

[eslint]每个then()都应该返回一个值或throw(promise/always return) (参数)resolve:any

下面是一个屏幕截图,可以看到错误的位置:

谢谢你的帮助!

更新:
我改变了一些事情(加上一个承诺):

// The Cloud Functions for Firebase SDK to create Cloud Functions and setup triggers.
const functions = require('firebase-functions');

const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);


// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
// exports.helloWorld = functions.https.onRequest((request, response) => {
//  response.send("Hello from Firebase!");
// });

exports.DeleteColletionFunction = functions.firestore
    .document('exampleCollection/{exampleID}')
    .onDelete((snap, context) => {
        // Get an object representing the document prior to deletion
      // e.g. {'name': 'Marie', 'age': 66}
      const deletedValue = snap.data();
      const exampleID = context.params.exampleID;

      const BATCH_SIZE = 500;

      const database = admin.firestore();

      const commentsRef = database.collection('exampleCollection').doc(exampleID).collection("comments");

      commentsRef.doc('main').delete();

      const exampleRef = database.collection('exampleCollection').doc(exampleID).collection("exampleSubCollection");
      const deleteExamples = deleteCollection(database, exampleRef, BATCH_SIZE)
      return Promise.all([deleteExamples]);

   });



/**
 * Delete a collection, in batches of batchSize. Note that this does
 * not recursively delete subcollections of documents in the collection
 */
function deleteCollection (db, collectionRef, batchSize) {
    var query = collectionRef.orderBy('__name__').limit(batchSize)

    return new Promise(function (resolve, reject) {
      deleteQueryBatch(db, query, batchSize, resolve, reject)
    })
  }

  function deleteQueryBatch (db, query, batchSize, resolve, reject) {
    query.get()
.then((snapshot) => {
        // When there are no documents left, we are done
        if (snapshot.size === 0) {
          return 0
        }

      // Delete documents in a batch
      var batch = db.batch()
      snapshot.docs.forEach(function (doc) {
        batch.delete(doc.ref)
      })

      return batch.commit().then(function () {
        return snapshot.size
      })
    }).then(function (numDeleted) {
      if (numDeleted <= batchSize) {
        resolve()
        return
      }
      else {
      // Recurse on the next process tick, to avoid
      // exploding the stack.
      return process.nextTick(function () {
        deleteQueryBatch(db, query, batchSize, resolve, reject)
      })
    }
  })
    .catch(reject)
  }

现在,我在firebase控制台中发现错误:

referenceerror:未定义exampleid 在exports.deletecolletionfunction.functions.firestore.document.ondelete(/user_code/index.js:26:66) 在物体上。(/user_code/node_modules/firebase functions/lib/cloud functions.js:112:27) 下一个(本地) at/user-code/node-modules/firebase-functions/lib/cloud-functions.js:28:71 在等待程序中(/user_code/node_modules/firebase functions/lib/cloud functions.js:24:12) at cloudfunction(/user_code/node_modules/firebase functions/lib/cloud functions.js:82:36) at/var/tmp/worker/worker.js:728:24 在进程中。_tickdomaincallback(internal/process/next_tick.js:135:7)

谢谢你的帮助!