Importing dotenv in ES6 #89

Sparragus · 2015-09-10T15:07:06Z

Support on ES6 has been tricky for me. Yesterday I tried preloading dotenv with iojs -r dotenv/config index.js. However, it didn't work and I couldn't understand why. My app did nothing. After running the app, a second or two later it would finish without doing anything.

I ended up with a very simple way to use dotenv. I simply import it like this:

import {} from 'dotenv/config'
import somethingElse from 'somethingElse'
...
[the rest of your code]

This works because of how ES6 modules imports modules. Before doing anything else in a file (say index.js) it does all the imports first. It does a depth first traversal of these imports, executing any code inside it. If we import dotenv first, it will execute config and add any env variables before doing anything else in the code.

From ES6 In Depth: Modules:

When you run a module containing an import declaration, the modules it imports are loaded first, then each module body is executed in a depth-first traversal of the dependency graph, avoiding cycles by skipping anything already executed.

So, importing dotenv on the first line of a bootstrap file in an app will set the env vars for anything that might use them.

I suggest we add a brief section about importing dotenv with ES6 modules to the README. But before sending a pull request and wanted to open it up for discussion here.

Any thoughts?

The text was updated successfully, but these errors were encountered:

motdotla · 2015-09-10T19:08:42Z

@jcblw you've done some work with ES6 right?

maxbeatty · 2015-09-10T19:23:34Z

@Sparragus can you provide a little more code so we can try to reproduce? I've added some examples of how to use dotenv in various ways in #90 including ES6 preloading. Are you using babel or something else for your import syntax? I don't believe the latest node v4.0.0 supports that out of the box yet.

I would caution against using dotenv/config in any context but preloading because it'll be doing additional work parsing command line arguments. import dotenv from 'dotenv' should do the trick

jcblw · 2015-09-10T20:37:20Z

I believe since we are not exporting out a key fordotenv the default import behavior of babel @maxbeatty mentions should work.

import dotenv from 'dotenv'
dotenv.config()

I would also be interested in how your running into an issue with preloading the module. Can you post the version of node/iojs and dotenv that you are using?

Sparragus · 2015-09-10T22:44:15Z

@maxbeatty and @jcblw

I've uploaded a repo with sample code showing everything I mentioned on my first message.

All examples use [email protected], [email protected], and [email protected].

Clone it and then make sure you also pull all the branches. Here's a one-liner to do that.

Each branch has a README.md with details about that particular branch. Make sure to check it out.

Start by trying out the master branch. Install all the dependencies with npm install. Then run the app with npm start.

Then try the other two branches: preload-dotenv and import-dotenv-then-config.

Let me know how it goes.

maxbeatty · 2015-09-10T23:28:09Z

babel-node has a -r option which conflicts with node's option of the same name. If you move the argument to after the script name, log outputs the first line but the second which depends on environment variables is undefined. If you change your start script to use babel/register, everything works as expected.

node -r dotenv/config -r babel/register index.js

This is an issue with using babel-node. Because it's primarily a development tool and not something that would be used in production, I'm inclined to close this issue.

Sparragus · 2015-09-11T02:05:25Z

@maxbeatty I agree with you. I didn't know about babel-node providing a different -r than node. I also liked that run script better than the one I'm using. I'm using it and it works.

Thanks all for your comments.

colllin · 2016-02-10T00:32:06Z

On newer version of babel (v6.x?), this is what worked for me:

Add import 'babel-polyfill'; at the top of all app entrypoint files.

At the comand line...

$ npm install babel-polyfill babel-register --save
$ node --require 'dotenv/config' --require 'babel-register' index.js

Or using nodemon...

$ nodemon index.js --exec "node --require 'dotenv/config' --require 'babel-register'"

I've also found that this way (manually importing babel-polyfill in your entrypoint files) is an easy way to ensure consistency between running your es6 files in development mode (using 'babel-register') and running in production mode (using babel to transpile during deployment). Otherwise we ran into issues where babel-node automatically included the babel-polyfill, but then running babel on the same file didn't automatically include babel-polyfill, so you could end up with broken code on production that worked fine in your dev environment. We tried importing babel-polyfill manually but then when running babel-node, we received errors for importing the polyfill twice.

…red in a file not commited to repo. Note nodemon is being run with node instead of babel-node because dotenv can be passed a required module from command line using node's -r flag which is highjacked by babel-node, Therefore server/index.js is back to using babel-node inline.

kachkaev · 2016-11-30T16:20:48Z

node --require 'dotenv/config' --require 'babel-register' index.js worked perfectly for me, thanks @colllin!

Just a small note for those want to develop on Windows: you should remove quotes around the module names:

node --require dotenv/config --require babel-register index.js
nodemon index.js --exec "node --require dotenv/config --require babel-register"

Using this in package.json:

{
  // ...
  "scripts": {
    // ...
    "start": "nodemon src/ --exec \"node --require dotenv/config --require babel-register\"",
    "start:prod": "babel-node --require dotenv/config --require babel-register src/"
  }
  // ...
}

arvi · 2017-06-01T15:48:44Z

@Sparragus Thanks a lot. I was getting undefined on my dotenv config and changing it to import {} from 'dotenv/config'; worked for me. 😄

* document trimming behavior of values during parsing closes #197 * make comments conform to jsdoc 3 fixes #201 * document options for working with imports ref #206 #133 #89 * add exampe of using returned object from config

saeta-eth · 2018-05-15T21:20:20Z

I have the following lines on the index.js file:

import dotenv from 'dotenv';
dotenv.config({ path: path.join(__dirname, '.env') });

console.log(process.env.MY_ENV_VAR) is a string value which is fine, but if I try the same in other file console.log(process.env.MY_ENV_VAR) is undefined.

I've added import {} from 'dotenv/config' to this other file and process.env.MY_ENV_VAR is now a string value.
It's really weird, but works for me.

Thanks @Sparragus.

uds214125 · 2018-06-07T08:37:29Z

You should follow this step as also mentioned in dotenv documentation.
#133

it is working fine in all the files.
0. in package.json
"start": "nodemon --require dotenv/config app.js --exec babel-register"

create config.js or env.js with these contents
import dotenv from 'dotenv'
dotenv.config({ silent: true });
in server.js/app.js or your root file.
import _ from './config.js';
check in another file
console.log('env : ', process.env);

djmattski · 2018-06-26T04:02:15Z

For anyone using Babel - this saved me: https://www.npmjs.com/package/babel-plugin-dotenv

onwuvic · 2018-06-28T14:44:26Z

@uds214125 Your method works fine for me. But I didn't have to preload the 'dotenv/config' on my script.

kaleidoscope18 · 2019-03-27T17:59:57Z

@slorenzo Since I had the same weird behaviour as you, I found out it's because, as it has been quoted above :

When you run a module containing an import declaration, the modules it imports are loaded first, then each module body is executed in a depth-first traversal of the dependency graph, avoiding cycles by skipping anything already executed.

It means that the imports are executed first, so executes import dotenv from 'dotenv'; which is simply importing node_module/dotenv and all other imports including your other file that won't have the custom .env data.
Then it would execute dotenv.config({ path: path.join(__dirname, '.env') }); which fetchs the custom .env data.

When you put import {} from 'dotenv/config', it would immediately import the .env data.

To summarize :
1- import dotenv from 'dotenv' is executed first (if you put it before all imports, of course)
2- all other imports are made
3- fetch .env with dotenv.config({ path: path.join(__dirname, '.env') });

bflemi3 · 2019-04-29T17:51:34Z

does this not work for you?

import 'dotenv/config`

Alexzanderk · 2019-07-09T09:11:25Z

does this not work for you?
import 'dotenv/config`

good job the best way to import, I don't know why on the top import to a variable!

izznogooood · 2019-09-11T16:25:40Z

does this not work for you?
import 'dotenv/config`
good job the best way to import, I don't know why on the top import to a variable!

Because this does not work in node v12.10.0

(node:19322) ExperimentalWarning: The ESM module loader is experimental.
internal/modules/esm/default_resolve.js:79
  let url = moduleWrapResolve(specifier, parentURL);
            ^

Error: Cannot find module /home/anders/dev/kaboom/node_modules/dotenv/config imported from /home/anders/dev/myfamily-api/src/index.mjs
    at Loader.resolve [as _resolve] (internal/modules/esm/default_resolve.js:79:13)
    at Loader.resolve (internal/modules/esm/loader.js:73:33)
    at Loader.getModuleJob (internal/modules/esm/loader.js:152:40)
    at ModuleWrap.<anonymous> (internal/modules/esm/module_job.js:43:40)
    at link (internal/modules/esm/module_job.js:42:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}

webhacking · 2019-09-18T07:01:42Z

import * as dotenv from 'dotenv';
dotenv.config()

Weffe · 2019-10-07T18:44:37Z

Just in case anyone is using esm to get es module syntax, then you can combine it with dotenv like so:

node -r esm -r dotenv/config main.js

This preloads your dotenv values and ensures that your references to them in your es modules will work properly.

naeem-gitonga · 2019-11-15T13:59:51Z

import { config } from 'dotenv';
config();

alex-r89 · 2020-01-26T13:26:24Z

import { config } from 'dotenv';
config();

The result of this is the env variables inside a parsed parent object, why is this?

IE if I console.log(config()) I get:

{
  parsed: {
    NODE_ENV: 'dev',
    DB_NAME: 'default',
    DB_TYPE: 'postgres',
    DB_HOST: 'localhost',
    ...rest of my .env file contents
  }
}

AntonioGomes42 · 2021-12-21T15:28:06Z

I made a project, to show how it worked for me. https://github.com/AntonioGomes42/DotEnv-with-ES6-COMMOM-JS- . It was the only way i could find to make dotenv work with '.env' file an so. I hope it could help someone!

MackKaputo · 2021-12-24T16:14:09Z

import dotenv from "dotenv"
import path from "path"
const __dirname = path.resolve()
dotenv.config({ path: path.join(__dirname, './.env') })

CherryDT · 2021-12-24T16:17:05Z

@MackKaputo This has the same problem as explained above unless you put it into a separate module only for this purpose and then import that module at the top of your main module.

Naibeye · 2022-01-05T11:46:23Z

For anyone using Babel - this saved me: https://www.npmjs.com/package/babel-plugin-dotenv

It is worked

motdotla · 2022-01-16T09:11:33Z

Hi everyone. We've updated the docs to clarify this for ESM. It is right at the top fold now:

https://github.com/motdotla/dotenv#2-as-early-as-possible-in-your-application-import-and-configure-dotenv

Hyzyr · 2022-02-01T13:54:08Z

import dotenv from 'dotenv';

dotenv.config({path: 'config.env'});

jeanbmar · 2022-03-09T11:23:18Z

Hi everyone. We've updated the docs to clarify this for ESM. It is right at the top fold now:

https://github.com/motdotla/dotenv#2-as-early-as-possible-in-your-application-import-and-configure-dotenv

How do you deal with custom path with this?

ashen780 · 2022-04-28T09:07:04Z

import 'dotenv/config'; console.log(process.env.DATABASE_HOST_TEST);

works for node version v16.14.2

alexcroox · 2022-06-24T13:59:37Z

All these examples that work across files don't seem to show how to set the config, e.g a custom path.

joeflan · 2022-06-28T20:56:58Z

@alexcroox One thing that worked for me (but I don't know if it's completely correct) to get the path working was:

import * as dotenv from 'dotenv'
dotenv.config({path:"custom/path/filename"})

motdotla · 2022-06-28T23:56:41Z

@alexcroox good point!

Yes, @joeflan is correct here. I'll update the README to communicate that better.

bitdom8 · 2022-07-03T14:49:01Z

Path is default to ./root/.

To add path to current directory (Dir), we need this code inside of the file that we want all variables to be imported

import dotenv from 'dotenv'
import path from 'path'

import {fileURLToPath} from 'url';
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
dotenv.config({ path: path.join(__dirname, '.env') });
// const express = require('express')
import express from 'express';

server.js and .env can should be in the same directory if you don't manipulate the path.join(__dirname.

You can reach the variables process.env.myvariable. Just be sure it works and print all variables: console.log(process.env)

Thanks

jarodsim · 2022-08-25T02:25:29Z

import { config } from 'dotenv'

joshh71390 · 2022-12-07T17:28:18Z

now sure why so much stress import {config} from 'dotenv"

config()

CherryDT · 2022-12-07T18:45:50Z

now sure why so much stress import {config} from 'dotenv"

config()

This will lead to surprises depending on how some modules import other modules, for the reasons I explained here: #89 (comment)

hsuabina · 2023-03-23T16:52:02Z

@SrBrahma This explains it all very well: https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/

Then think about it again - If you have files like this:
// main.js
import dotenv from 'dotenv'
dotenv.config()

console.log('MAIN', process.env.STUFF) 

import './sub.js'
// sub.js
console.log('SUB', process.env.STUFF)
... and you run STUFF=abc node main.js, then you will get this:
SUB undefined
MAIN abc
Remember this sentence from the article on the section about evaluation:

Just as with instantiation, this is done as a depth first post-order traversal.

Because for any module before itself is evaluated, any imported modules from top to bottom are evaluated (unless they already were evaluated elsewhere before), the imported module dotenv is evaluated first, and then sub is evaluated, and oops, dotenv.config() didn't run yet. Afterwards, now that all imported modules of main were evaluated, main itself can be evaluated, and dotenv.config() is called, but for the poor sub module that's already too late.

This is solved with import 'dotenv/config' because this loads the environment already as part of its own evaluation.

@CherryDT , is this correct though?

I just tested it and I get this output:

SUB abc
MAIN abc

crizardevelop · 2023-07-27T17:20:14Z

Don't try to add a name to the file (like variables.env). Just create a file with the name ".env"

pujan789 · 2023-08-31T14:04:35Z

import 'dotenv/config';

CherryDT · 2023-10-19T14:14:30Z

@SrBrahma This explains it all very well: https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/
Then think about it again - If you have files like this:
// main.js
import dotenv from 'dotenv'
dotenv.config()

console.log('MAIN', process.env.STUFF) 

import './sub.js'
// sub.js
console.log('SUB', process.env.STUFF)
... and you run STUFF=abc node main.js, then you will get this:
SUB undefined
MAIN abc
Remember this sentence from the article on the section about evaluation:

Just as with instantiation, this is done as a depth first post-order traversal.

Because for any module before itself is evaluated, any imported modules from top to bottom are evaluated (unless they already were evaluated elsewhere before), the imported module dotenv is evaluated first, and then sub is evaluated, and oops, dotenv.config() didn't run yet. Afterwards, now that all imported modules of main were evaluated, main itself can be evaluated, and dotenv.config() is called, but for the poor sub module that's already too late.
This is solved with import 'dotenv/config' because this loads the environment already as part of its own evaluation.
@CherryDT , is this correct though?

I just tested it and I get this output:
SUB abc
MAIN abc

You are right, I made a mistake while writing this post.

Of course it works because I incorrectly wrote to use STUFF=abc node main.js, so there isn't even any .env file involved!

What I meant to write (and changed now accordingly) was to use node main.js and creating a .env file with STUFF=abc in it.

volodalexey · 2023-11-04T14:15:19Z

Doesn't work for my case. I have nextjs and expressjs applications alognside and I want to start expressjs using .env.local from nextjs.
content index.ts:

import dotenv from "dotenv";
dotenv.config({
  path: resolve(process.cwd(), ".env.local"),
});
import { env } from "./env" // <-- throws zod parse error

content env.ts:

import z from "zod";
const configSchema = z.object({
  NEXTAUTH_URL: z.string().url(),
});
export const env = configSchema.parse(process.env);

The problem is because process.env inside index.ts is not the same as process.env inside env.ts.
Running index.ts as tsx index.ts (tsx).

Any ideas how to solve this?

CherryDT · 2023-11-04T14:18:31Z

That's exactly the scenario I explained why import dotenv from 'dotenv'; dotenv.config() doesn't work and import 'dotenv/config' has to be used.

However, in your case you need to pass arguments to .config so you can't use that method. Instead, you can move your dotenv setup into a separate module and include that in your main module at the very top:

index.ts:

import './setupDotEnv';
import { env } from "./env";

setupDotEnv.ts:

import dotenv from "dotenv";
dotenv.config({
  path: resolve(process.cwd(), ".env.local"),
});

env.ts:

import z from "zod";
const configSchema = z.object({
  NEXTAUTH_URL: z.string().url(),
});
export const env = configSchema.parse(process.env);

paraschouhan15 · 2023-11-25T02:34:34Z

import dotenv from 'dotenv'
import express from "express";
import colors from "colors"

dotenv.config();

const app = express();

app.get('/', (req, res) => {
res.send(
"

Welcome to my aapp

"
);
})
//port

const port = process.env.PORT

app.listen(port, () => {
console.log(Server running on mode ${process.env.DEV_MODE} port number ${port}.bgYellow.black)
})
I am getting undefined...in console PORT number AND developmnt mode

luiskurihara · 2024-01-11T14:03:18Z

does this not work for you?
import 'dotenv/config`

YOU SAVED ME THANKSSS

motdotla · 2024-01-19T01:44:59Z

for those coming across this we are starting to recommend using dotenvx

https://github.com/dotenvx/dotenvx

runs anywhere (cross-platform)
multiple enviornments
encrypted envs

dotenvx will work the same whether you are running node, bun, deno, python, anything.

abhinavph21 · 2024-02-25T11:51:42Z

Doesn't work for my case. I have nextjs and expressjs applications alognside and I want to start expressjs using .env.local from nextjs. content index.ts:
import dotenv from "dotenv";
dotenv.config({
  path: resolve(process.cwd(), ".env.local"),
});
import { env } from "./env" // <-- throws zod parse error
content env.ts:
import z from "zod";
const configSchema = z.object({
  NEXTAUTH_URL: z.string().url(),
});
export const env = configSchema.parse(process.env);
The problem is because process.env inside index.ts is not the same as process.env inside env.ts. Running index.ts as tsx index.ts (tsx).

Any ideas how to solve this?

read this,
https://nextjs.org/docs/app/api-reference/next-config-js/env,
in nextjs, you have to create next.config.js for environment variables

jonjieviduya · 2024-03-19T11:34:39Z

I tried every single code here but it always says "process is not defined"

GohilTushar · 2024-05-25T04:30:04Z

import dotenv from "dotenv";
import path from 'path';
dotenv.config({
path:path.resolve(<Your path for .env>)
});

maxbeatty mentioned this issue Sep 10, 2015

add examples for how to use module in different ways #90

Merged

Sparragus closed this as completed Sep 11, 2015

tikotzky mentioned this issue Dec 20, 2015

importing dotenv using ES6 imports #114

Closed

maxbeatty mentioned this issue Jul 13, 2016

Impossible to set options in some cases #145

Closed

kachkaev mentioned this issue Dec 5, 2016

Suppress errors of missing .env file for production #58

Closed

maxbeatty added a commit that referenced this issue Jun 20, 2017

document options for working with imports ref #206 #133 #89

9d6d904

MNITD mentioned this issue Jul 15, 2018

@babel/node Cannot resolve module with --require babel/babel#8229

Closed

This was referenced Dec 8, 2022

I believe since we are not exporting out a _key_ fordotenv the default import behavior of babel @maxbeatty mentions should work. #701

Closed

@maxbeatty and @jcblw #702

Closed

motdotla mentioned this issue Mar 18, 2024

Attempting to import into ES6 yields error #821

Closed

Importing dotenv in ES6 #89

Importing dotenv in ES6 #89

Comments

Sparragus commented Sep 10, 2015

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maxbeatty commented Sep 10, 2015

jcblw commented Sep 10, 2015

Sparragus commented Sep 10, 2015

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paraschouhan15 commented Nov 25, 2023

Welcome to my aapp

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