What is .env?

In this tutorial, we will implement a .env into our NodeJS app to store environment variables inside of it.
Here I will introduce how you can use environment variables and for what you should use them. Let's Go.

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dotenv

Dotenv is a zero-dependency module that loads environment variables from a .env file into process.env. Storing configuration in the environment separate from code is based on The Twelve-Factor App methodology.

init npm in our directory

npm init -y

Install express (for the server) and dotenv

npm install express dotenv

Install nodemon to start the server in watch mode.
Watch mode => Restarting the server on file change

npm install -D nodemon

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Create a file called ".env" in the root directory and insert a variable using NAME=VALUE.

We want to put in out PORT variable to define the port on which our server will start on that is PORT=3001.

In a real-world application, you want to store your API key and any kind of sensitive data like passwords here.

Importing Express

const express = require('express');

Initialize the app

const app = express();

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Configure dotenv

This will load the variables we created in the .env file into the process.env so we can use it using process.env.VARIABLE_NAME

require('dotenv').congif();

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Getting the port from the .env file and set 3000 as a fallback.

const port = process.env.PORT || 3000;

Starting the server using the port :

app.listen(port, () => console.log(server on :${ port }));

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nodemon index.js

[nodemon] 2.0.4
[nodemon] to restart at any time, enter 'rs'
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json
[nodemon] starting `node index.js`

Now, this should be console logged. If we wouldn't run require('dotenv').config(); in the index.js then the log should be 'server on:3000' because then our fallback value would be applied for the port variable.

server on:3001

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Originally here => https://rahulism.tech/article/what-is-env-file/

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😀 SIMPLE