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I am just trying to config the .env file on my main file.

but somehow it's not working but the error is wrong, its showing undefined but its already there

1st try

require('dotenv').config({ path: `${__dirname}/../.env` })
2nd try
import * as dotenv from 'dotenv'
dotenv.config()
3rd try
import 'dotenv/config'
somehow the .env is not loading.
executing the file by
ts-node main.ts
.env file
SESSION_SECRET = uq07nyvn4xadskdg
COOKIE_SECRET = 0k5kb4qi8shhi7u0n
DB_HOST = 127.0.0.1
DB_PORT = 3306
DB_USER = root
DB_PASS = root
DB_NAME = db_name
database connection
export const db = createPool({
  host: process.env.DB_HOST,
  port: process.env.DB_PORT,
  user: process.env.DB_USER,
  password: process.env.DB_PASS,
  database: process.env.DB_NAME,
session
const sessionD = session({
  secret: process.env.SESSION_SECRET,
  resave: true,
  saveUninitialized: true,
  store: new MySQLStore({
    host: process.env.DB_HOST,
    port: process.env.DB_PORT,
    user: process.env.DB_USER,
    password: process.env.DB_PASS,
    database: process.env.DB_NAME,
                You'll need to show the .env file contents and the code that tries to use the env variables.  See minimal reproducible example.
– Guy Incognito
                Dec 14, 2020 at 21:20
                You'll need to show the code that tries to use the env variables.  See minimal reproducible example.
– Guy Incognito
                Dec 14, 2020 at 21:25
dotenv doesn't tell typescript anything. All it does it put whatever is in your .env into process.env at runtime. This doesn't change any types of anything.
So you're dealing with process.env that seems to have this type:
export interface ProcessEnv {
    [key: string]: string | undefined;
Which means you can't assign it to a value that can't be undefined.
const myVar: string = process.env.WHATEVER
// Type 'string | undefined' is not assignable to type 'string'.
//   Type 'undefined' is not assignable to type 'string'.
The fix is to handle the undefined case. What if someone forgets the .env file or removes some its entries? What should your code do in that case?
Perhaps, provide a default:
const whatever: string = process.env.WHATEVER ?? 'whatever default'
Or maybe throw an error:
let whatever: string
if (process.env.WHATEVER) {
  whatever = process.env.WHATEVER
} else {
  throw new Error("WHATEVER environment variable is not set")
TL;DR: Handle the undefined case.
The types expected are string or string array, and you are passing environment variables that are not recognizable by the typescript. So you have to typecast your environment variable as a string like this for all your .env variables and the error will be removed.
secret: process.env.SESSION_SECRET as string;
You can read about Type assertion here.
                Thank you, this helped me out, I was trying to create a object from the .env and pass it as config, but ...   new Redis({host: process.env.REDIS_HOST as string, port: process.env.REDIS_PORT  as string,})   This helped me out
– Kristian Vasilev
                Nov 1, 2022 at 16:53
This worked for me in 2022:
I suggest you create a type declaration for your variables. Name it env.d.ts and save it with the following content in your source directory, e. g. /src
declare namespace NodeJS {
  interface ProcessEnv {
    readonly SESSION_SECRET: string
    readonly COOKIE_SECRET: string
    readonly DB_HOST: string
    readonly DB_PORT: string
    readonly DB_USER: string
    readonly DB_PASS: string
    readonly DB_NAME: string
NB: Port is a string because dotenv handles everything as string
Now make sure the env.d.ts is included in the include section in your tsconfig.json (pseudocode - ... stands for your other properties:
  "include": [
    "src/**/*.d.ts",
Now the variables should be recognized by typescript.
                if you want a full example of this solution: dev.to/asjadanis/parsing-env-with-typescript-3jjm
– Etienne Duverney
                Jan 19 at 6:49
I had the same issue.This is how I solved it.
Import dotenv as
import * as dotenv from 'dotenv'
dotenv.config()
Make sure you have the .env file at the root directory.Once you are sure it is there try and print the values and view them.Now they should be loading correctly.
Now once all the values are loaded just put the values from the env likeprocess.env.{ENV_KEY}
Now you can access the env value.If they cannot be loaded in typescript just write process.env.{ENV_KEY} as string.This should solve the TS issue
        
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