How to retrieve data from MongoDB with NodeJS

To retrieve data from the MongoDB database we will use find, findOne with nodeJS promise. 

In the first example, we use findOne which will return the first occurrence where “this”:1 in the collection test in the database testdb. This will be an array including the _id and the fields of the document.

const MongoClient = require('mongodb').MongoClient;

// Connection url
const url = 'mongodb://192.168.1.203:27017';
options = {
    useNewUrlParser: true
};

MongoClient.connect(url, options).then(function (ok) {
        
       db1 = ok;
       dbName = 'testdb';
        return db1.db(dbName).collection('test').findOne({"this":1});

    })
    .then(function (dbs) {
console.log(dbs);
db1.close();
    });

This will return the data in nodeJS

$ node test.js
{ _id: 5bab60e785f572e55fe09165, this: 1, another: 'dfjfjdfdf' }

You can also use find().toArray to return all the documents with a field equals to the same value (here this: 1).

const MongoClient = require('mongodb').MongoClient;
// Connection url
const url = 'mongodb://192.168.1.203:27017';
options = {
    useNewUrlParser: true
};

MongoClient.connect(url, options).then(function (ok) {
        
       db1 = ok;
       dbName = 'testdb';
        return db1.db(dbName).collection('test').find({"this":1}).toArray();

    })
    .then(function (dbs) {
console.log(dbs);
db1.close();
    });

This will return the following result in an array because I inserted three identical documents using insertOne:

$ node test.js
[ { _id: 5bab60e785f572e55fe09165, this: 1, another: 'dfjfjdfdf' },
  { _id: 5bab61018df000e560655d2d, this: 1, another: 'dfjfjdfdf' },
  { _id: 5bab6110b8724ae561d7191d, this: 1, another: 'dfjfjdfdf' } ]