Firestore将值添加到数组字段 [英] Firestore Add value to array field

问题描述

我正在尝试使用Firebase云功能将聊天室的ID添加到数组字段中的用户文档中.我似乎无法弄清楚写入数组字段类型的方法.这是我的云功能

Im trying to use Firebase cloud functions to add the id of a chatroom to the users document in an array field. I cant seem to figure out the way to write to an array field type. here is my cloud function

  exports.updateMessages = functions.firestore.document('messages/{messageId}/conversation/{msgkey}').onCreate( (event) => {
    console.log('function started');
    const messagePayload = event.data.data();
    const userA = messagePayload.userA;
    const userB = messagePayload.userB;   

        return admin.firestore().doc(`users/${userA}/chats`).add({ event.params.messageId }).then( () => {

        });

  });

这是我的数据库的外观

非常感谢任何提示，我是Firestore的新手.

any tips greatly appreciated, Im new to firestore.

推荐答案

从文档中，他们添加了一个新操作来添加或删除数组中的元素.在此处了解更多信息: https://firebase.google.com/docs/firestore /manage-data/add-data

From the docs, they added a new operation to append or remove elements from arrays. Read more here: https://firebase.google.com/docs/firestore/manage-data/add-data

示例:

var admin = require('firebase-admin');
// ...
var washingtonRef = db.collection('cities').doc('DC');

// Atomically add a new region to the "regions" array field.
var arrUnion = washingtonRef.update({
  regions: admin.firestore.FieldValue.arrayUnion('greater_virginia')
});
// Atomically remove a region from the "regions" array field.
var arrRm = washingtonRef.update({
  regions: admin.firestore.FieldValue.arrayRemove('east_coast')
});

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