NodeJs, MongoDb - Why is my code duplicating documents instead of updating them? - node.js

Question

I want to find an existing document in MongoDB by its _id. Everything works except trying to edit existing just creates a new document with a new _id instead of updating the current. It seems that it skips if (this._id) { in the model file. Very frustrated because I can see the issue but cannot find a fix. Thanks in advance!
plant.js controller:
exports.getEditPlant = (req, res, next) => {
const editMode = req.query.edit;
if (!editMode) {
console.log('Not Edit Mode');
}
const dbId = req.params._id;
Plant.findById(dbId)
.then(plant => {
if (!plant) {
console.log('Err');
res.redirect('back');
}
res.render('account/edit-plant', {
pageTitle: 'Edit Plant',
path: '/account',
plant: plant,
edit: editMode
});
}).catch(err => {
console.log(err);
});
};
exports.postEditPlant = (req, res, next) => {
const updatedName = req.body.common_name;
const scientific_name = req.body.scientific_name;
const updatedImg = req.body.image_url;
const slug = req.body.slug;
const updatedPlant = new Plant(updatedName, scientific_name, updatedImg, slug, new ObjectId(id));
updatedPlant.addMyPlant()
.then(plant => {
res.redirect('home');
}).catch(err => {
console.log(err);
})
};
plant.js model:
const mongodb = require('mongodb');
const getDB = require('../util/database').getDB;
module.exports = class Plant {
constructor(common_name, scientific_name, image_url, slug, id) {
this.common_name = common_name;
this.scientific_name = scientific_name;
this.image_url = image_url;
this.slug = slug;
this._id = id;
}
addMyPlant() {
const db = getDB();
let dbOp;
if (this._id) {
dbOp = db
.collection('myplants')
.updateOne({ _id: new mongodb.ObjectId(this._id) }, { $set: this });
} else {
dbOp = db.collection('myplants').insertOne(this);
}
return dbOp
.then(result => {
})
.catch(err => {
console.log(err);
});
}
static getMyPlants() {
const db = getDB();
return db.collection('myplants')
.find().toArray()
.then(plants => {
return plants;
}).catch(err => {
console.log(err);
});
}
static findById(dbId) {
const db = getDB();
return db
.collection('myplants')
.find({ _id: new mongodb.ObjectId(dbId) })
.next()
.then(plant => {
return plant;
})
.catch(err => {
console.log(err);
});
}
}

Answer 1

You need to assign the known _id to the ObjectID outside of the query.
In your code, you instantiate a new ObjectID inside your query but the value you passed in is not found.
This is a simplified version of your class with tests:
const mongodb = require('mongodb').MongoClient;
const ObjectID = require('mongodb').ObjectID;
const url = "mongodb://localhost:27017/mydb";
class Plant {
constructor(name) {
this.name = name;
}
// this method pulls all the records for me to test results
getAll() {
mongodb.connect(url, { useUnifiedTopology: true }, (err, db) => {
if (err) throw err;
var dbo = db.db("mydb");
dbo.collection("plants").find({}).toArray(function (err, result) {
if (err) console.log(err);
console.log(result);
db.close();
});
})
}
// update single record
updateMyPlant() {
mongodb.connect(url, { useUnifiedTopology: true }, (err, db) => {
if (err) console.log(err);
console.log("Mongo connected...");
const dbo = db.db("mydb");
// if you know the _id
// instantiate a variable outside your query
// now const id is the same as the _id you wants to query
const id = ObjectID("5fd8a1100617b03d8c737da0");
const myquery = { "_id": id };
const newvalues = { $set: { "name": "Marlon Brando" }};
try {
dbo.collection("plants").updateOne(myquery, newvalues, (err, res) => {
if (err) console.log(err);
console.log("update result", res.result, res.upsertedId);
db.close();
})
}
catch (e) {
console.log(e);
}
})
}
}
// test
const plant = new Plant("Alexa");
plant.updateMyPlant();
plant.getAll();
module.exports = Plant;
/**
* Logs:
* Mongo connected...
update result {
n: 1,
nModified: 1,
ok: 1
}
null
[{
_id: 5 fd8a1100617b03d8c737da0,
name: 'Marlon Mickey',
scientific_name: 'Brittain'
}]
*/
As you can see the _id is retained while the properties you want to change are updated.
See more info about ObjectID here