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reactjs - 反应具有许多回报的 Firebase 云功能

问题描述

有什么方法可以updateQuestions在 foreach + ref 中设置我的变量？或者我必须做两个不同的云功能？我想返回一个巨大的更新updateQuestions，但我需要从基于 firebase 数据的 foreach 中返回数据..

这是我的功能：

exports.deleteQuestion = functions.database.ref('questions_for_mars/{pushId}').onDelete(event => {
      const original = event.val()
      idQuestion = event.key
      authorQuestion = original.author
      //console.log('event', original.answers)

      return admin.database().ref('counter/questions_active').once('value').then((snapshot) => {


        var questions_active = snapshot.val()

        var updateQuestions = {};



        updateQuestions['/counter/questions_active'] = questions_active - 1
        updateQuestions['/my_questions/' + authorQuestion + '/' + idQuestion] = null
        updateQuestions['/my_questions_send/' + authorQuestion + '/' + idQuestion] = null
        updateQuestions['/questions/' + idQuestion] = null
        //updateQuestions['/my_answers/' + authorQuestion + '/' + idQuestion] = null



        event.child('answers').forEach(child => {


          var mars = child.key

          return admin.database().ref('/mars/' + mars + '/counter/answers_active').once('value').then((snapshot) => {

            var answers_active = snapshot.val()

            updateQuestions['/my_answers/' + mars + '/' + idQuestion] = null
            updateQuestions['/mars/' + mars + '/counter/answers_active'] = answers_active - 1


          });

          console.log('TOTO', updateQuestions)
        });
        console.log('UPDAYE', updateQuestions)

        return admin.database().ref().update(updateQuestions)

      })


    });

标签： reactjsfirebasegoogle-cloud-functions

解决方案

您似乎使用的是旧版本的 Firebase SDK for Cloud Functions，请参阅https://firebase.google.com/docs/functions/beta-v1-diff。您绝对应该更新它（请参阅本文档中的说明）。

然后，对于您的event.child('answers').forEach(child => {})循环，您需要使用Promise.all()来管理对数据库的并行异步查询。

您将以Promise.all()与查询数组相同的顺序在对应于履行值的数组中收到结果。

所以下面的代码应该可以解决问题（未经测试）：

exports.deleteQuestion = functions.database.ref('questions_for_mars/{pushId}').onDelete((snapshot, context) => {
    const original = snapshot.val()
    idQuestion = snapshot.key
    authorQuestion = original.author
    //console.log('event', original.answers)

    var updateQuestions = {};

    return admin.database().ref('counter/questions_active').once('value')
        .then((snapshot) => {

            var questions_active = snapshot.val();

            updateQuestions['/counter/questions_active'] = questions_active - 1
            updateQuestions['/my_questions/' + authorQuestion + '/' + idQuestion] = null
            updateQuestions['/my_questions_send/' + authorQuestion + '/' + idQuestion] = null
            updateQuestions['/questions/' + idQuestion] = null
            //updateQuestions['/my_answers/' + authorQuestion + '/' + idQuestion] = null

            var queries = [];

            snapshot.child('answers').forEach(child => {
                var mars = child.key
                queries.push(admin.database().ref('/mars/' + mars + '/counter/answers_active').once('value'))
            });

            return Promise.all(queries);
        })
        .then(results => {
            results.forEach(snapshot => {
                var answers_active = snapshot.val()
                //Here you need to extract the value of mars from snapshot.key
                //I let you do this piece of code!! 
                updateQuestions['/my_answers/' + mars + '/' + idQuestion] = null
                updateQuestions['/mars/' + mars + '/counter/answers_active'] = answers_active - 1
            });
            return admin.database().ref().update(updateQuestions)
        });

})

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