node.js - nodejs mongodb don't wait the update

Question

I have a problem with my mongoDB script

It looks like that :

const mongodb = require("mongodb").MongoClient;
const class = 'Com'
const a = [{name: 'John', tempData: 'test'}, {name: 'Marie', tempData: 'test'}, {name: 'Luc', tempData: 'test'}]
mongodb.connect(
    'mongodb://localhost:27017/', {
        useNewUrlParser: true,
        useUnifiedTopology: true
    },
    async (err, client) => {

        a.map(async (item) => {
    let e = await client.db('project').collection('persons').findOne({
                class: class
            });

    if (!e.students) {
                _.set(e, 'students', [item])
            }else{
                const findData = item.name 
                const d = await _.find(e.students, findData )
                if(!_.isUndefined(d)){
                    const z = _.indexOf(e.students,d)
                    e.representants[z] = _.merge(e.students[z],item) 
                }else{
                    console.log('Other case')
                    e.students.push(item)
                }
                console.log('new object : ',e.students)
            }
            
            await client.db('project').collection('persons').findOneAndUpdate({class: class}, {$set: e}, {returnNewDocument: true}, () => {
 console.log('Updated')
});
    });
});

My problem is that in my first loop, my e should not have students array, and in the second loop, it should find the same object with the students array, but mongo return the old object, without array, like it has not the time to update the object in database before second loop

I think it's a time problem because my three logs 'Updated' appear after the three 'new object' log, like this :

new object : [{...}]
new object : [{...}]
new object : [{...}]
Updated
Updated
Updated

But it shoud be like this :

new object : [{...}]
Updated
new object : [{...},{...}]
Updated
new object : [{...},{...},{...}]
Updated

I've already try to add promise but it does not work, but maybe i've add it at the wrong line

If u have the solution, it'll save me couple of hours

Thanks in advance

question from:https://stackoverflow.com/questions/65916152/nodejs-mongodb-dont-wait-the-update

Answer 1

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