Firebase Firestore:从文档数组中追加/删除项目 [英] Firebase Firestore: Append/Remove items from document array

问题描述

我试图从 Firestore 文档内的数组中附加/删除项目，但每次替换整个数组而不是附加新值时.我已经尝试了以下两种方法:

I am trying to append/remove items from an array inside of a Firestore Document but every time the entire array is replaced instead of the new value being appended. I have tried both of the following:

batch.setData(["favorites": [user.uid]], forDocument: bookRef, options: SetOptions.merge())

batch.updateData(["favorites": [user.uid]], forDocument: bookRef)

我知道我可以使用对象/字典代替数组，但这意味着存储不相关的其他数据(例如密钥)，我需要的只是存储在数组中的 ID.Firestore 中目前可以实现这种功能吗?

I know that instead of an array I can use an object/dictionary but that would mean storing additional data that is irrelevant (such as the key), all I need is the ID's stored inside the array. Is this something that is currently possible in Firestore?

推荐答案

实际上，现在是可能的.最新更新 db.collection.updateData方法实际上将新项目附加到数组而不是替换它.示例用法可以在 Firebase 文档中找到.

Actually, nowadays it is possible. With latest updates db.collection.updateData method actually appends new item to array instead of replacing it. Example usage can be found in Firebase documentation.

如果需要手动操作，可以使用

If you need to do it manually, you can use

FieldValue.arrayUnion([user.uid])

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