Javascript object printing as object object

Question

I am very new to both node and mongo db.I was creating a connection from node to Mongo and trying the CRUD Operations.My operations are defined in operations.js and i am calling the functions from index.

The issue i am facing is when i am printing the callback parameter from

coll.find({}).toarray() - that is result i am getting the desired output as

[
  {
    _id: 5ea4843b0f28320524d23f14,
    name: 'Vadonut',
    description: 'Test Vadonut'
  },
]

but when i am printing the result from index.js which is a result of the callback from the functions in operation.js i am getting the output as

[object Object]

Can i get help on this?????

index.js :

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const dboper = require('./operations')
const url = "mongodb://localhost:27017/";
const dbname = "dishes";

MongoClient.connect(url,(err,client)=>{
    assert.equal(err,null);

    console.log("Connected correctly correct to the server");

    const db =client.db(dbname);


    dboper.insertdocument(db,{"name":"Vadonut","description":"Test Vadonut"},'dishes',(result)=>{
        console.log('Insert Document:\n'+result);

        dboper.finddocument(db,'dishes',(result)=>{
           console.log("Found Documents :\n"+result);
    })

})

****operations.js****

const assert = require('assert');

exports.insertdocument = (db,document,collection,callback)=>{
    const coll = db.collection(collection);
    coll.insertOne(document,(err,result)=>{
        assert.equal(err,null);
        console.log("Inserted " + result.result.n + "documents inserted into the collection"+collection);
        console.log(result.ops);
        callback(result);

    })

};

exports.finddocument = (db,collection,callback)=>{
    const coll = db.collection(collection);
    coll.find({}).toArray((err,docs)=>{
        assert.equal(err,null);
        console.log(docs);
        callback(docs);
    })
};

Did you try JSON.stringify on your result object?

alimcharaniya
– alimcharaniya

2020-04-25 20:10:47 +00:00
Commented Apr 25, 2020 at 20:10 — alimcharaniya
– alimcharaniya, Commented Apr 25, 2020 at 20:10

jfriend00 · Accepted Answer · 2020-04-25 20:21:51Z

[object Object] is the default/automatic string conversion for an object.

So, if you use an object anywhere in a string manipulation expression such as this:

let x = {greeting: "hello"};
let str = "I would like to say the greeting " + x;
console.log(str);

Then, the JS interpreter will try to convert your object x to a string and that default string conversion will be [object Object] so you will get a result of:

 I would like to say the greeting [object Object]

What you need to do is either avoid using a Javascript object anywhere in a string expression or explicitly convert the object to JSON with JSON.stringify() before involving it in a string expression.

I would replace this:

console.log("Inserted " + result.result.n + "documents inserted into the collection"+collection);

with this:

console.log("Inserted ",  result.result.n, "documents inserted into the collection", collection);

Then, you're passing whole objects to console.log() and it will do its normal object display on them rather than let JS try to auto-convert them to a string.

You could also manually convert those objects to string form with JSON.stringify(result.result.n) and then use them in string expressions.

Nayan · Accepted Answer · 2020-04-25 20:13:41Z

3

It is because of two different behavior of console log with "," and "+".

let user = {"_id":"5ea4843b0f28320524d23f14", "name":"Vadonut"};
  
console.log("doc"+ user)

console.log("doc", user)

Also the check this

answered Apr 25, 2020 at 20:13

Nayan

6586 silver badges16 bronze badges

1 Comment

Tejas Hegde Over a year ago

@Nayan..yes that was the reason..ty for the help

Abishek · Accepted Answer · 2020-04-25 20:12:20Z

1

Can you try with JSON.stringify(result)

like this

dboper.insertdocument(db,{"name":"Vadonut","description":"Test Vadonut"},'dishes',(result)=>{
        console.log('Insert Document:\n'+JSON.stringify(result));

        dboper.finddocument(db,'dishes',(result)=>{
           console.log("Found Documents :\n"+JSON.stringify(result));
    })

answered Apr 25, 2020 at 20:12

Abishek

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2 Comments

Tejas Hegde Over a year ago

@Abhishek..Yes it helps..thanks..but i am not able to understand why this is happening.Even when i am getting the result object in operations.js then i am able to print that Json object.

Abishek Over a year ago

had the code been console.log(result), you would have seen the data. if you concatenate with a string, then you need to use JSON.stringify. Or, as @nayan mentioned in the other answer, you can do like console.log("Found Documents: \n", result)

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