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firebase - Firestore 事务更新多个文档

问题描述

我想更新一个集合中的文档。

my_collection
     document_1
        field_1
        field_2
     document_2
        field_1
        field_2

我的代码：

exports.aggregateUsers = 
functions.firestore.document('users/{userId}').onWrite(function(change, 
context) {
const document = change.after.exists ? change.after.data() : null;
const oldDocument = change.before.data() || null;

return firestore.runTransaction(function(transaction) {
    var oldInstanceRef;
    var instanceRef;

    var oldInstanceDoc;
    var instanceDoc;
    if (document != null) {
        instanceRef = firestore.collection("counters").doc("instance_counter").collection("instances").doc(document.instance);
        instanceDoc = transaction.get(instanceRef);

        var newNumberOfUsers = (instanceDoc.data().number_of_users || 0) + 1;
        transaction.set(instanceRef, { number_of_users: newNumberOfUsers });
    } 
    if (oldDocument != null) {
        oldInstanceRef = firestore.collection("counters").doc("instance_counter").collection("instances").doc(oldDocument.instance);
        oldInstanceDoc = transaction.get(oldInstanceRef);

        var newPrevNumberOfUsers = (oldInstanceDoc.data().number_of_users || 0) + 1;
        transaction.set(instanceRef, { number_of_users: newPrevNumberOfUsers });
    }


}).catch(function(error) {
    console.log("invalid-argument", error.code, error.message);
});
});

错误：

instanceDoc.data is not a function

由于应用程序流量低，我正在使用云功能中的交易来汇总用户数量，而不是使用分布式计数器。我的问题是如何更新每个文档中的字段值？谢谢

标签： firebasetransactionsgoogle-cloud-firestore

解决方案

我猜你忘记了异步/等待。

尝试这个：

  1. asynctransaction参数前
  2. await前transaction.get(<some_ref_here>) 

return firestore.runTransaction(async transaction => {
    var oldInstanceRef;
    var instanceRef;

    var oldInstanceDoc;
    var instanceDoc;
    if (document != null) {
        instanceRef = firestore.collection("counters").doc("instance_counter").collection("instances").doc(document.instance);
        instanceDoc = await transaction.get(instanceRef);

        var newNumberOfUsers = (instanceDoc.data().number_of_users || 0) + 1;
        transaction.set(instanceRef, { number_of_users: newNumberOfUsers });
    } 
    if (oldDocument != null) {
        oldInstanceRef = firestore.collection("counters").doc("instance_counter").collection("instances").doc(oldDocument.instance);
        oldInstanceDoc = await transaction.get(oldInstanceRef);

        var newPrevNumberOfUsers = (oldInstanceDoc.data().number_of_users || 0) + 1;
        transaction.set(instanceRef, { number_of_users: newPrevNumberOfUsers });
    }


}).catch(function(error) {
    console.log("invalid-argument", error.code, error.message);
});

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