Connecting MongoDB to MERN app - mongodb

Question

I am in the process of trying to connect my MongoDB to my MERN web application and was wondering the best resource for information on this type of thing. Basically, I have a MERN web app, electron desktop app, and react native mobile app that I am trying to all connect to one MongoDB, but I can't find any information on this that directly answers how it should be wired. I can provide more details if needed.

Answer 1

Make sure you are using the database username and password not the account username and password from Mlab.
In MLab, formerly MongoLab, do the following:
Navigate to Users
Add Database User
Choose your username and password
Now you can test this on the shell with mongo ds061374.mlab.com:61374/yourdb -u <dbuser> -p <dbpassword>.

Answer 2

I hope you have already signed up to mongodb and created a project there.
Below is the integration process to get your MERN application connected to MongoDB online cluster.
Make sure you have the following libraries installed dotenv, mongoose.
Create a folder in your project root directory that will hold your configuration file, Eg config_folder
Create a .js file, Eg dbConnnect.js
Create a create a dotenv file to hold the key for your MongoDB cluster by just creating a fine file on your project root folder and name it .env. NOTE no prefix required while naming this file.
login to your MongoDB and navigate to Projects, select your project then navigate to Databases -> Clusters -> connect -> connect your application -> copy the connection string.
Navigate back to your .env file and create a variable and paste the connection string as shown below.
MONGODB_URI = 'your_connection_string_from_mongoDB'
Inside dbConnect.js add the following code.
const mongoose = require('mongoose')
const dbConnect = async() => {
try {
const connected = await mongoose.connect(process.env.MONGODB_URI, {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex: true,
useFindAndModify: false
});
console.log(`Connected ${connected.host}`)
} catch (error) {
console.log(`error : ${error.message}`)
}
}
module.exports = {
dbConnect
}
Now you need to call the above block in your server file using the code below.
const { dbConnect } = require('./config/dbConnect')
const dotenv = require('dotenv')
dotenv.config()
dbConnect();
That's the end of the integration process. It worked for me and I hope it'll help.

Answer 3

If you want to connect your MongoDB with the MERN app you can use the mongoose package for that, let me tell you the steps.
Packages you will need : mongoose,nodemon,express
Note*:- Make sure you know how to use Mongo Atlas.
1- Step 1- create db.js file in your main directory.
//import mongoose
const mongoose = require("mongoose")
//make connection variable
const connection = mongoose.connect("mongodb+srv://<username>:<password>#cluster0.en0mzco.mongodb.net/?retryWrites=true&w=majority")
//the username and password will be the same as your cluster username and password.
//export the connection variable
module.exports={
connection
}
2- Step 2- Create index.js file for the server
//import express
const express = require("express")
//import connection from db.js
const {connection} = require("./db.js")
//define post
const port = 4000
const app = express()
//Start server code
app.listen(port,async()=>{
try{
//mongo db all operations are done in an async manner so make sure you use async/await
await connection
//on the successful connection this msg will show in your terminal
console.log("Connected to db")
}catch(err){
console.log(err)
}
console.log("Server is runnig on port number",port)
})
3- Step 3- Make sure you add this line to your package.json inside scripts
"server":"nodemon index.js"
//Now run the server by running this command in your terminal
npm run server
Also, I am putting my youtube video for full stack web development, where you will get all the processes of how to do all the setup.
Youtube Link: Fullstack web development in 1hour