ESLint - 'process' is not defined

Question

I am using ESLinter for a simple node project. Below is the only code I have in index.js:

const express = require('express'); const app = express(); app.get('/', (req, res) => { res.send({ hi: 'there' }); }); const PORT = process.env.PORT || 5000; app.listen(PORT);

I am using VSCode editor. It automatically runs ESLint for JS code.

In the IDE, I see below error for last but one line -

[eslint] 'process' is not defined. (no-undef)

Any Idea what's wrong?

does ESLINT have some way of informing it you are linting nodejs code? — Jaromanda X
– Jaromanda X, Commented Jun 17, 2018 at 5:37
You probably haven't configured eslint correctly. eslint.org/docs/user-guide/configuring#specifying-environments — Felix Kling
– Felix Kling, Commented Jun 17, 2018 at 5:38
Thanks @FelixKling - It was so dumb of me not looking into .eslintrc.json file. I had accidentally selected browser default global variables. Your link hinted me to that. Now, the error is gone! — ArunKolhapur
– ArunKolhapur, Commented Jun 17, 2018 at 5:42

mikemaccana · Accepted Answer · 2022-04-26 09:11:37Z

384

When I got error I had "browser": true instead of "node": true.

I have fixed this with following config for .eslintrc.json file-

{ "env": { "node": true, "commonjs": true }, "extends": "eslint:recommended", "rules": { "indent": [ "error", "tab" ], "linebreak-style": [ "error", "unix" ], "quotes": [ "error", "single" ], "semi": [ "error", "always" ] }, "parserOptions": { "ecmaVersion": 2015 } }

Thanks @FelixKling and @Jaromanda X for quick responses.

edited Apr 26, 2022 at 9:11

mikemaccana

126k113 gold badges441 silver badges544 bronze badges

answered Jun 17, 2018 at 5:47

ArunKolhapur

7,0755 gold badges22 silver badges32 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Mark Swardstrom Over a year ago

This got rid of my ESlint 'URL' is not defined, too.

try_catch Over a year ago

In my case I was missing the node: true on my env eslint config file.

Josh Over a year ago

Adding the "node" : true worked for me also with this issue.

Arno Teigseth Over a year ago

Thought I selected "node" in the wizard at npm init @eslint/config but seems I didn't heh

Jon Watte Over a year ago

Note that this isn't how it's done in version 9+. You need to import the "node" globals instead of the "browser" globals.

|

crtag · Accepted Answer · 2019-04-10 04:59:49Z

Adding "node": "true" to an existing list of environments will do the job, too

"env": { "node": true, "commonjs": true, "browser": true, "es6": true }

dryniex · Accepted Answer · 2019-06-26 16:09:54Z

Add .eslintrc file to root of your project (if you don't already have one) and define globals to ignore

{ "globals": { "process": true } }

Make sure you use process.env though out the project but only in a single configuration file. Consider adding no-process-envrule.

https://eslint.org/docs/rules/no-process-env

This is useful if you're using a bundler like Parcel, which exposes process in a browser context.
This is the correct way if your're implementing a frontend application.

Géry Ogam · Accepted Answer · 2024-04-16 08:21:02Z

49

In the new ESLint configuration file eslint.config.js, the env property has been removed so you should use the languageOptions.globals property:

import globals from 'globals'; export default [ { languageOptions: { globals: { ...globals.node, } } } ];

edited Apr 16, 2024 at 8:21

answered Apr 22, 2023 at 18:03

Géry Ogam

8,4345 gold badges53 silver badges89 bronze badges

2 Comments

LeggoMaEggo Dec 1, 2024 at 9:40

This is the one that did it for me! Thank you! if you use --init to create the eslint.config.js file.

Xevion May 3 at 8:14

For those wondering, you can scope this configuration to just a single file. This is useful in my case where I have frontend and backend code; I scoped it to a central file for verifying environment variables, but needs direct access to the process.env object. See @t3-oss/env-nextjs if you're curious.

youngwolf · Accepted Answer · 2021-03-28 06:21:45Z

36

If you have eslint installed, add env: { node: true } to the .eslintrc.js file

answered Mar 28, 2021 at 6:21

youngwolf

4915 silver badges4 bronze badges

Comments

M. Hamza Rajput · Accepted Answer · 2022-08-17 17:30:57Z

This config helped me and can help others too.

{ "parser": "babel-eslint", "parserOptions": { "ecmaFeatures": { "jsx": true, "modules": true }, "ecmaVersion": 2020, "sourceType": "module", "useJSXTextNode": true, "warnOnUnsupportedTypeScriptVersion": false }, "root": true, "env": { "browser": true, "es6": true, "node": true, "commonjs": true }, "extends": [ "eslint:recommended"], } }

I just had to add "parser": "babel-eslint" to my .eslintrc.json file

Jon Watte · Accepted Answer · 2024-08-17 05:17:52Z

As of version 9 of eslint, the old style of configuration is deprecated. The way it's supposed to be done now is:

import globals from "globals"; import pluginJs from "@eslint/js"; export default [ {languageOptions: { globals: globals.node }}, pluginJs.configs.recommended, ];

(obviously, different plugins if you use typescript.)

This is extra annoying, because even if you create the config file with "eslint --init" and say you're running in node, it will by default use globals.browser rather than the correct globals.node.

M. Hamza Rajput · Accepted Answer · 2022-08-17 17:29:25Z

When working on the node js project. This might help you. It is working on my end.

module.exports = { "env": { "node": true, "browser": true, "commonjs": true, "es6": true }, "extends": "eslint:recommended", "globals": { "Atomics": "readonly", "SharedArrayBuffer": "readonly" }, "parserOptions": { "ecmaVersion": 2018 }, "rules": { } };

tHeSiD · Accepted Answer · 2022-03-03 18:28:40Z

If you are getting the error even after settng "node": true, remember to install @types/node with

npm i -D @types/node yarn add -D @types/node

Erhan Yaşar · Accepted Answer · 2024-11-28 08:41:29Z

None of the answers satisfies the valid and ideal working solution currently.

First, the file is updated from .eslintrc.js to eslint.config.js or eslint.config.mjs in my case as it's already cited above.
For those wondering how to create one, running npm init @eslint/config@latest will result an interactive command line questions to create a config template with defaults.
Secondly, this template shipped with an object called languageOptions as stated below.

{languageOptions: { globals: globals.browser }},

The problem with that is, this will lead to an error as the enquirer's problem shown with the screenshot below;

If you read the previous answers from @Géry Ogam & @Jon Watte, they will lead you to try either one of those alternatives;

{languageOptions: { globals: { ...globals.node }}},

or

{languageOptions: { globals: globals.node }},

which might result more errors if any of browser object methods used as shown below when running linter even though it fixes the error enquirer ask;

TL;DR

What to do to surpass all of those unwanted linter errors to let us making use of both cases?

Adding both globals.node and globals.browser into the globals property under languageOptions will resolve the issue and produce no more errors regarding the use cases for both environments.

{languageOptions: { globals: { ...globals.node, ...globals.browser }}},

1j01 · Accepted Answer · 2024-02-07 23:50:18Z

For a single file, when most other scripts are meant to run in a browser environment, you can add a special comment to the top of a file:

/* eslint-env node */

Note that it has to be a block comment style; an inline style comment (//) will not work.

M. Hamza Rajput · Accepted Answer · 2022-08-17 17:25:39Z

Add these env lines in your `.eslintrc.js` file.

module.exports = { "env": { "browser": true, "commonjs": true, "node": true, "es2021": true, "jest": true }, "extends": "eslint:recommended", "parserOptions": { "ecmaVersion": "latest" }, "rules": { } }

Ankur Marwaha · Accepted Answer · 2024-02-16 12:37:48Z

Seems you need to enable Node Core library Within WebStorm:

Go to File -> Settings -> Languages & Frameworks -> Node.js and NPM
Make sure that 'Node.js Core library is enabled' by pressing Enable button.
Click OK for saving settings.

G-Force · Accepted Answer · 2025-03-27 17:16:55Z

Elements of the above solutions are helpful, and also show the answers over time. The main thing I saw was at v9+, there is a new file system for configurations.

Several of the solutions above reference them, but here's what I discovered, and document for anyone else who comes across this:

config files:

.eslintrc.js .eslintrc.json eslint.config.js eslint.config.mjs

with the v9+, you'll get one of the last 2 of these files based on the answers you provide in the command line initialization (also referenced in other answers above)

Things to note: the first 2 files are now legacy and are useless, so remove or rename them.

The config file that worked, and removed the error (originally stated in this question) was the eslint.config.js/mjs file, and here is my working entry (edited from script auto-generated):

import globals from "globals"; import pluginJs from "@eslint/js"; /** @type {import('eslint').Linter.Config[]} */ export default [ { languageOptions: { globals: { ...globals.node } } }, pluginJs.configs.recommended, ];

last notes: This answer solves the exact "process" question originally asked, and will make the lint error disappear. Others have suggested adding the globals.browser entry and have both. This is needed only if you're building FE code/need browser, but strictly, isn't required to answer this question. Add it if needed. (I'm a minimalist in enabling kinda person)

Hope this helps someone :)

João Gabriel Carvalho · Accepted Answer · 2025-04-10 18:59:45Z

0

Changing it to languageOptions: { globals: globals.node} worked for me.

answered Apr 10 at 18:59

João Gabriel Carvalho

414 bronze badges

1 Comment

Quentin Apr 10 at 20:17

Please don't add "thank you" as an answer. Once you have sufficient reputation, you will be able to vote up questions and answers that you found helpful. - From Review

ventuno · Accepted Answer · 2025-05-09 06:34:35Z

I had a same problem after I created my react project via VITE.

I solved it like this:

in .env file :
(You should create your .env file inside your root path) Your enviromental variables should be started with VITE_

VITE_BACKEND_URL=http://localhost:5000/api VITE_ASSET_URL=http://localhost:5000 VITE_STH=SOMETHING

Then inside your codes you can access to your variables as below:

// `${import.meta.env.<name of your variable>}` `${import.meta.env.VITE_BACKEND_URL}/places/${props.id}`

hackel · Accepted Answer · 2025-07-01 15:48:32Z

Extending the answers already provided, if you're working on a browser-based app, you really don't want to allow the Node API in your browser files, so you should restrict your eslint config to support node only in config files. e.g.

{ files: ['**/*.config.js'], languageOptions: { globals: globals.node, }, },

You can add any additional files that are run by node and not in the browser to the files array.

Aryan Kashyap · Accepted Answer · 2025-08-15 19:33:17Z

import globals from 'globals'; export default [ { languageOptions: { globals: { ...globals.node, }, ecmaVersion: 12, }, rules: { // Your specific rules here } } ];

Just add this

...globals.node,

as eslint not recorginse node global variable

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

P Varga · Accepted Answer · 2021-01-19 20:56:54Z

-4

Another remedy for this issue is to simply import process from "process".

Even though it's not strictly necessary, one could argue it's better practice anyway.

answered Jan 19, 2021 at 20:56

P Varga

20.4k14 gold badges77 silver badges118 bronze badges

2 Comments

PhillipJacobs Nov 29, 2024 at 5:03

Down votes with no comments - wow!

P Varga Dec 2, 2024 at 3:47

@PhillipJacobs And on a working solution :/

Collectives™ on Stack Overflow

ESLint - 'process' is not defined

19 Answers 19

6 Comments

Comments

2 Comments

2 Comments

Comments

1 Comment

Comments

Comments

Comments

TL;DR

Comments

1 Comment

Add these env lines in your `.eslintrc.js` file.

Comments

Comments

Comments

1 Comment

Comments

Comments

1 Comment

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

19 Answers 19

6 Comments

Comments

2 Comments

2 Comments

Comments

1 Comment

Comments

Comments

Comments

TL;DR

Comments

1 Comment

Add these env lines in your .eslintrc.js file.

Comments

Comments

Comments

1 Comment

Comments

Comments

1 Comment

2 Comments

Linked

Related

Add these env lines in your `.eslintrc.js` file.