从Firestore文档获取字段 [英] Get field from Firestore document

问题描述

是否可以从Firestore对象中提取和解析单个字段，而无需运行For Each或先将其传递给数组?

Is it possible to extract and parse just a single field from a Firestore object without running a For Each or alternatively first passing this to an array?

具体来说，我提取了一个文档，如下所示(工作正常):

Specifically, I have pulled a single document as below (below working):

const docRef = admin
      .firestore()
      .collection("profiles")
      .doc(profileId);

由此，我想解析一个字段(accountBalance)，但无法做到这一点(假设可以，但不能):

From this I would like to parse a single field (accountBalance) but not able to do this (assumed to work but does not):

const accountBalance = docRef.accountBalance;

这需要解析吗?

推荐答案

是否可以从Firestore对象中提取和解析单个字段，而无需运行For Each

Is it possible to extract and parse just a single field from a Firestore object without running a For Each

是的，有可能.根据官方文档，您可以使用DocumentSnapshot的 get()函数:

Yes, it is possible. According to the official documentation, you can achieve this using DocumentSnapshot's get() function:

检索fieldPath指定的字段.如果文档或字段不存在，则返回undefined.

Retrieves the field specified by fieldPath. Returns undefined if the document or field doesn't exist.

在代码中，应如下所示:

In code, should look like this:

docRef.get().then(function(doc) {
    if (doc.exists) {
        console.log("profileId: ", doc.get("profileId"));
    } else {
        console.log("No such document!");
    }
}).catch(function(error) {
    console.log("Error getting document:", error);
});

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