uri is returning undefined. Mongodb connection is not been established - node.js

Question

enter image description here I need to know what's the problem. I am not getting the message on console for establishment of Mongodb database connection.
Here is a link to the error picture. https://drive.google.com/file/d/14cdAgAjfVX6R7pXND-FbjbK_3r-A3F-J/view?usp=share_link
server.js file
const express = require('express');
const cors = require('cors');
const mongoose = require('mongoose');
require('dotenv').config();
const app = express();
const port = process.env.port || 5000;
app.use(cors());
app.use(express.json());
// debugger
var uri; // Define outside
if(process.env.ATLAS_URI){
uri = process.env.ATLAS_URI; // Assign inside the block
}
mongoose.connect(uri, { useNewUrlParser: true, useCreateIndex: true}
);
const connection = mongoose.connection;
connection.once('open', () => {
console.log("MongoDB database connection established successfully");
})
const exercisesRouter = require('./routes/exercises');
const usersRouter = require('./routes/users');
app.use('/exercises', exercisesRouter);
app.use('/users', usersRouter);
app.listen(port, ()=> {
console.log(`Server is running on port: ${port}`);
});
.env file
ATLAS_URI = mongodb+srv://tripsy25:Mongo#123#cluster0.lwpkrde.mongodb.net/?retryWrites=true&w=majority
I tried to debug the code and found that uri was coming as undefined. Do I need to convert the password in ATLAS_URI to some other format?

Answer 1

The .env file must be located in the root folder of your project. And you should run the project from the root folder. Therefore:
Example 1
server.js
.env
Run it with node ./server.js
Example 2
src
|-server.js
.env
Run it with node ./src/server.js

Answer 2

You did one mistake in .env file
you did
ATLAS_URI = mongodb+srv://tripsy25:Mongo#123#cluster0.lwpkrde.mongodb.net/?retryWrites=true&w=majority
But you have to use url of atlas as an string
ATLAS_URI = "mongodb+srv://tripsy25:Mongo#123#cluster0.lwpkrde.mongodb.net/?retryWrites=true&w=majority"

Answer 3

The .env file must be located on the root folder and you must include it in the file where ever you need it at the very top.
and a few changings you just need to do and the things are good to go.
require('dotenv').config();
const express = require('express');
const cors = require('cors');
const mongoose = require('mongoose');
mongoose.set('useNewUrlParser', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
mongoose.set('useUnifiedTopology', true);
const app = express();
const port = process.env.port || 5000;
app.use(cors());
app.use(express.json());
mongoose.connect(process.env.ATLAS_URI)
.then(() => {
console.log("DB connection successful")
app.listen(port, () => {
console.log(`app listening on port ${port}`);
})
})
.catch((err) => {
console.log(err)
})
const exercisesRouter = require('./routes/exercises');
const usersRouter = require('./routes/users');
app.use('/exercises', exercisesRouter);
app.use('/users', usersRouter);
I am not getting why you just create a var for ATLAS_URI. Just keep the code simple and neat and clean.