Mongo Query Returning Empty Array

Question

I'm a total beginner at this and am using a tutorial to learn the basics of the MEAN stack. I am trying to return the documnents in my database to a web page but am instead receiving an empty array.

I have created a cluster on Mongodb Atlas called mytasklist. Inside here I created a database called mytasklistdb. Inside this I have a table (object) called mytasklistdb.mytasklisttutorial. My understanding of this is limited and so maybe I'm making a huge error somewhere here. I have experience of SQL but not Mongo and so the whole 'clusters' and 'collections' thing is new to me.

Anyway my code is as follows. I took the string for the database connection from the Mongo connection tab.

var express = require('express');
var router = express.Router();
var mongojs = require('mongojs');
var db = mongojs('mongodb+srv://myusername:[email protected]/test?retryWrites=true&w=majority', ['mytasklisttutorial']);

router.get('/tasks', function(req, res, next){
    db.mytasklistdb.find(function(err, tasks){
        if(err){
            res.send(err);
        }
        res.json(tasks);
    });
});

module.exports = router;

My database objects look like this:

_id:5db5f1f31c9d440000c3e7fe
title:"Walk the dog"    -   this is a string
isDone:false      -     this is boolean

I'm just getting an empty array but in the tutorial the guy is getting these 'documents'. What am I doing wrong?

EDIT: I realised that the 'tasks' part of the tutorial example was relating to a database called 'tasks'. Mine is called 'mytasklistdb'. I therefore changed this. I also added a parameter with the name of my collection to the line passed in to mongojs.

I have changed my code above to reflect this

can you share the video link and can you update question with your db schema ? — 0xAnon
– 0xAnon, Commented Oct 28, 2019 at 17:57
Do you have collection named tasks in the db. If yes you are not passing it as second parameter to the connection constructor. OR before the queries const collection = db.collection('tasks'); then do db.collection.find(...) — ambianBeing
– ambianBeing, Commented Oct 28, 2019 at 18:14
ambianBeing I have added these things - I think you were right but it still doesn't work — user1480135
– user1480135, Commented Oct 28, 2019 at 18:28
@user1480135 I think there is 1 more change that you need to do. the URL is connecting to a db called test which i suppose is not correct. Change the URL to something like: mongojs('mongodb+srv://myusername:[email protected]/mytasklistdb?retryWrites=true&w=majority', ['mytasklisttutorial']); If the db name is mytasklistdb and collection is mytasklisttutorial — ambianBeing
– ambianBeing, Commented Oct 28, 2019 at 18:35

user1480135 · Accepted Answer · 2019-10-28 19:17:12Z

1

The solution was to replace 'task' and 'test' with the name of my db. As follows:

var express = require('express');
var router = express.Router();
var mongojs = require('mongojs');
var db = mongojs('mongodb+srv://James:[email protected]/mytasklistdb?retryWrites=true&w=majority', ['mytasklisttutorial']);

router.get('/tasks', function(req, res, next){
    db.mytasklisttutorial.find(function(err, tasks){
        if(err){
            res.send(err);
        }
        res.json(tasks);
    });
});

module.exports = router;

answered Oct 28, 2019 at 19:17

user1480135

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Matheus Hatje · Accepted Answer · 2019-10-28 18:01:29Z

0

My guess is that you are not passing your query, just the callback in the find() method, probably you need to do something like this:

db.tasks.find({},function(err, tasks){
    if(err){
        res.send(err);
    }
    res.json(tasks);
});

answered Oct 28, 2019 at 18:01

Matheus Hatje

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1 Comment

user1480135 Over a year ago

It's still empty unfortunately.

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