How to use data from a query in mongoDB?

Question

I want to use the data that return from Mongodb’s 'find()' to, through a foreach, create a table using the array that returns from Mongodb, and after the table is ready, generate a PDF, but I am not able to access the result data outside the connection function with DB.

   db.open( function (err, mongoclient) {
    mongoclient.collection('postagens', function (err, collection) {
        collection.find().toArray(function(err, results){
            if(err){
                res.json(err);
            } else {
                res.send(results);
            }
            mongoclient.close();
            return results
        })

    })
})

let conteudoPDF = {
    content:[
        {text: 'Teste de PDF', style: 'header'},
        'Teste com pdfMake',
        {
            table:{
                body:[
                    [ 'Id Usuário', 'Id Post', 'Título', 'Texto'],
                   /*Aqui irá o forEach para gerar a tabela*/

                ]
            }
        }
    ]
}

The 'Results' variable contains the JSON array I need, and I want to have access to this data outside the DB connection function, and 'Return' is not exporting this data outside the function

Answer 1

You can fill in the contents of the PDF by invoking a function for this in the callback successful consultation, thus:

 db.open(function(err, mongoclient) {
    mongoclient.collection('postagens', function(err, collection) {
        collection.find().toArray(function(err, results) {
            if (err) {
                res.json(err);
            } else {
                // invocar a função que preenche o pdf aqui
                preencherPDF(results);
                res.send(results);
            }
            mongoclient.close();
            return results
        })

    })
})

function preencherPDF(conteudo) {
    let conteudoPDF = {
        content: [{
                text: 'Teste de PDF',
                style: 'header'
            },
            'Teste com pdfMake',
            {
                table: {
                    body: [
                        ['Id Usuário', 'Id Post', 'Título', 'Texto'],
                        /*Aqui irá o forEach para gerar a tabela*/
                        conteudo.forEach((item) => {
                            console.log(item)
                        });
                    ]
                }
            }
        ]
    }
}