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environment variables are undefined in reactJS

I'm working on an application utilizing the spotify API. I have secrets I want to keep in the form of Client ID's , endpoints and the like. I've done everything I am required to do to successfully use environment variables in react. This includes prefixing my variables with REACT_APP_ and making sure .env is in the root folder. In the code shown below, I am able to briefly console.log my environment variables.
const login = useRef(`${process.env.REACT_APP_AUTH_ENDPOINT}?client_id=${process.env.REACT_APP_CLIENT_ID}&redirect_uri=${process.env.REACT_APP_REDIRECT_URI}&response_type=${process.env.REACT_APP_RESPONSE_TYPE}`);
yet when I try to access them in a render here it is undefined
{!token ?
<a href={login.current}>Login to spotify</a>
:
<button onClick={logout}>Logout </button>
}
{
token ?
<form onSubmit={searchArtists}>
<input type='text' onChange={e => setSearchKey(e.target.value)} placeholder='search for a song or artist' />
<button type='{submit}'>Search</button>
</form>
:
<h2>Please login</h2>
}
}
I made sure to use a useRef hook just to make sure that the values persist so I can use my secrets when I want to return a render for react. This was to no avail.
I have a feeling it has to do with when I refresh? or perhaps my environment clears after I go to my redirect URI?
I also didn't bother importing dotenv because from what I've read , React handles all of that on its own.
For reference here is the .env file as well:
REACT_APP_CLIENT_ID =*************************
REACT_APP_REDIRECT_URI =https://swipewithspotify.vercel.app/
REACT_APP_AUTH_ENDPOINT =https://accounts.spotify.com/authorize
REACT_APP_RESPONSE_TYPE =token
If there's some concept that I have wrong I'd love an explanation if possible or any kind of light to be sure shed on this problem.

Best way to Add env variable if we got undefined type error, I solved the same problem. Please follow these steps.
npm install dotenv-webpack --save-dev
Create .env file under root folder
3.create env variable as
REACT_APP_MY_API=342432...
Create webpack.config.js file under the root folder with the following content
add this same code into webpack.config.js file.
const Dotenv = require('dotenv-webpack');
module.exports = {
plugins: [
new Dotenv()
]
}
And you can use where do you want in your root folder or src folder
access variables like this
const apiKey = process.env.REACT_APP_MY_API;
When you add a variable into env file and still got undefined make sure you restart your server

next.js environment variables are undefined (Next.js 10.0.5)

I am coding a website with Next.js and I tried to add google Tag Manager.
I followed the tutorial on the Next.js Github example but for some reasons I can't access to my environment variables.
It says my variable is undefined.
I created a file .env.local on my project folder (at the same level as components, node_modules, pages, etc)
In this file I created a variable like this (test purpose) :
NEXT_PUBLIC_DB_HOST=localhost
And on my index page I tried this code :
console.log("test ", process.env.NEXT_PUBLIC_DB_HOST);
But in my console I get a "test undefined".
I tried to put my variable into an .env file instead, without success.
What I am doing wrong ?

This envs just works in Server Side. To access this envs in Client Side, you need declare in the next.config.js
This way:
module.exports = {
reactStrictMode: true,
env: {
BASE_URL: process.env.BASE_URL,
}
}

Create .env (all environments), .env.development (development environment), and .env.production (production environment).
Add the prefix NEXT_PUBLIC to all of your environment variables.
NEXT_PUBLIC_API_URL=http://localhost:3000/
Use with prefix process.env
process.env.NEXT_PUBLIC_API_URL
Stop the server and restart it:
npm run dev
I hope it works.
This solution for latest version of nextJs (above 9)

Restarting the server worked for me.
Edit & save .env.local
Stop the server and restart it, npm run dev
You should get an output on the next line like this:
> klout#0.1.0 dev
> next dev
Loaded env from [path]/.env.local

For those using NextJS +9 and looking for environment variables in the browser, you should use the NEXT_PUBLIC_ prefix. Example:
NEXT_PUBLIC_ANALYTICS_ID=123456789
See documentation for reference.

After spending countless hours on this, I found that there is a tiny little paragraph in both the pre and post nextjs 9.4 documentation:
(Pre-9.4) https://nextjs.org/docs/api-reference/next.config.js/environment-variables (same as this answer)
Next.js will replace process.env.customKey with 'my-value' at build time.
(^9.4) https://nextjs.org/docs/basic-features/environment-variables
In order to keep server-only secrets safe, Next.js replaces process.env.* with the correct values at build time.
Key words being BUILD TIME. This means you must have set these variables when running next build and not (just) at next start to be available for the client side to access these variables.

This is my next.config.js file.
/** #type {import('next').NextConfig} */
const nextConfig = {
reactStrictMode: true,
env: {
BASE_URL: process.env.NEXT_PUBLIC_SITE_URL,
},
};
module.exports = nextConfig;
Restart the server and it worked fine. using Nextjs 12.1.0 with typescript

In my case, Im pasting REACT_APP_API_URL instead of NEXT_PUBLIC_API_URL.

Adding with the most recent version of the documentation on this, v12+.
Using the next.config.js file you can specify server and client variables:
module.exports = {
serverRuntimeConfig: {
// Will only be available on the server side
mySecret: 'secret',
secondSecret: process.env.SECOND_SECRET, // Pass through env variables
},
publicRuntimeConfig: {
// Will be available on both server and client
staticFolder: '/static',
},
}
You can still use an env.local file, and pass the variable in to the next.config.js file. For example:
publicRuntimeConfig: {
DB_URL: process.env.DB_URL
}
And then you can access the variable like this:
import getConfig from 'next/config';
const { publicRuntimeConfig } = getConfig();
publicRuntimeConfig.DB_URL;

Config.get() Not Getting Configuration From File: "custom-environment-variables.json" Nodejs, JavaScript

I am learning how to configure my Node.js App environment. For this I am using config module.
Below is my index.js file:
`
const config=require('config');
const express=require('express');
const app=express();
app.use(express.json()); //BUILT-IN EXPRESS MIDDLEWARE-FUNCTION
//CONFIGURATION
console.log('Current Working Environment:',process.env.NODE_ENV);
console.log('Name is:', config.get('name'));
console.log('Server is:', config.get('mail.host'));
console.log('Password is:', config.get('mail.password'));
`
I set NODE_ENV to production by the power shell command: $env:NODE_ENV="production".
My production.json file inside the config folder is:
`{
"name":"My Productoin Environmet",
"mail":{
"host": "Prod-Environment"
}
}`
And custom-environment-variables.json file is:
`{
"mail":{
"passwrod":"app_password"
}
}`
I set app_password to 12345678 by the power shell command : $env:app_password="12345678"
config.get() is supposed to look at various sources to look for this configurations including, json files, configuration files and also environment variables. But whenever I run my app, I get the following error:
`throw new Error('Configuration property "' + property + '" is not defined'); Error: Configuration property "mail.password" is not defined`
If I remove the line : console.log('Password is:', config.get('mail.password')); everything goes well. Please, guide me what is the solution?

Firstly you have a lot of syntactical errors for example in
custom-environment-variables.json
{
"mail":{
"password":"app_password"
}
}
Now if u need to store the password of your mail server in the environment variables
On windows
$env:app_password=12345
On Linux and OSX:
export app_password=12345
how to run ?
app.js
const config = require("config");
console.log("Mail Password: " + config.get("mail.password"));

i had the same problem because i didn't define an environment variable for storing the password of the mail server. So, my suggestion will be define your environment variable for storing the password using the below command line (mac) and then your code should work.
export app_password=/* the password you want to set */
how to define an environment variable for storing the password of the mail server.

While defining environment variables in command_prompt don't put space on either side of '=' sign.....
eg:
set app_password = 123456 -----> is wrong way
set app_password=123456 -----> will work

The issue in 99% of cases is in the name of the file in the config folder, storing your custom variables

To add on: make sure your file has .json extension.

How to mutate node-config in memory

I'm trying to mutate the value of my config in memory for testing, I've tried adding process.env.ALLOW_CONFIG_MUTATIONS=true in several spots in the application, as well as through the command line and my .env file.
The config.util.getEnv('ALLOW_CONFIG_MUTATION') method always returns undefined.
I've also tried using importFresh and MockRequest as per examples I've seen online, neither of which allow me to mutate the config in memory, and then reset the value later.
Does anyone have any idea about this?
Update: here's an example of what I'm trying to accomplish
const config = require (config);
const app = new App(config)
it(`does a thing with base config`, () => { ... }
it('does a thing with modified config, () => {
// here i would need to modify my config value and
// have it change the original config that's currently in
// application memory
config = newConfig
expect(config.get('newValues')).to.equal(true)
}
Thanks!

If it is the same config module that I have used (I think I is) then add a custom-environment-variables.js OR test.js with you test config.
test.js will need an ENV=test to work and the custom-environment-variables need something like (for Mac's and NPM) $ npm run funcTest -> yarn serverRunning && NODE_ENV=test wdio wdio.conf.js.
the JSON will look something like
{
test: 'Value'
}

npm global packages: Reference content files from package

I'm in the process of building an npm package which will be installed globally. Is it possible to have non-code files installed alongside code files that can be referenced from code files?
For example, if my package includes someTextFile.txt and a module.js file (and my package.json includes "bin": {"someCommand":"./module.js"}) can I read the contents of someTextFile.txt into memory in module.js? How would I do that?

The following is an example of a module that loads the contents of a file (string) into the global scope.
core.js : the main module file (entry point of package.json)
//:Understanding: module.exports
module.exports = {
reload:(cb)=>{ console.log("[>] Magick reloading to memory"); ReadSpellBook(cb)}
}
//:Understanding: global object
//the following function is only accesible by the magick module
const ReadSpellBook=(cb)=>{
require('fs').readFile(__dirname+"/spellBook.txt","utf8",(e,theSpells)=>{
if(e){ console.log("[!] The Spell Book is MISSING!\n"); cb(e)}
else{
console.log("[*] Reading Spell Book")
//since we want to make the contents of .txt accesible :
global.SpellBook = theSpells // global.SpellBook is now shared accross all the code (global scope)
cb()//callBack
}
})
}
//·: Initialize :.
console.log("[+] Time for some Magick!")
ReadSpellBook((e)=>e?console.log(e):console.log(SpellBook))
spellBook.txt
ᚠ ᚡ ᚢ ᚣ ᚤ ᚥ ᚦ ᚧ ᚨ ᚩ ᚪ ᚫ ᚬ ᚭ ᚮ ᚯ
ᚰ ᚱ ᚲ ᚳ ᚴ ᚵ ᚶ ᚷ ᚸ ᚹ ᚺ ᚻ ᚼ ᚽ ᚾ ᚿ
ᛀ ᛁ ᛂ ᛃ ᛄ ᛅ ᛆ ᛇ ᛈ ᛉ ᛊ ᛋ ᛌ ᛍ ᛎ ᛏ
ᛐ ᛑ ᛒ ᛓ ᛔ ᛕ ᛖ ᛗ ᛘ ᛙ ᛚ ᛛ ᛜ ᛝ ᛞ ᛟ
ᛠ ᛡ ᛢ ᛣ ᛤ ᛥ ᛦ ᛧ ᛨ ᛩ ᛪ ᛫ ᛬ ᛭ ᛮ ᛯ
If you require it from another piece of code, you will see how it prints to the console and initializes by itself.
If you want to achieve a manual initalization, simply remove the 3 last lines (·: Initialize :.) and use reload() :
const magick = require("core.js")
magick.reload((error)=>{ if(error){throw error}else{
//now you know the SpellBook is loaded
console.log(SpellBook.length)
})

I have built some CLIs which were distributed privately, so I believe I can illuminate a bit here.
Let's say your global modules are installed at a directory called $PATH. When your package will be installed on any machine, it will essentially be extracted at that directory.
When you'll fire up someCommand from any terminal, the module.js will be invoked which was kept at $PATH. If you initially kept the template file in the same directory as your package, then it will be present at that location which is local to module.js.
Assuming you edit the template as a string and then want to write it locally to where the user wished / pwd, you just have to use process.cwd() to get the path to that directory. This totally depends on how you code it out.
In case you want to explicitly include the files only in the npm package, then use files attribute of package.json.
As to particularly answer "how can my code file in the npm package locate the path to the globally installed npm folder in which it is located in a way that is guaranteed to work across OSes and is future proof?", that is very very different from the template thingy you were trying to achieve. Anyway, what you're simply asking here is the global path of npm modules. As a fail safe option, use the path returned by require.main.filename within your code to keep that as a reference.

When you npm publish, it packages everything in the folder, excluding things noted in .npmignore. (If you don't have an .npmignore file, it'll dig into .gitignore. See https://docs.npmjs.com/misc/developers#keeping-files-out-of-your-package) So in short, yes, you can package the text file into your module. Installing the module (locally or globally) will get the text file into place in a way you expect.
How do you find the text file once it's installed? __dirname gives you the path of the current file ... if you ask early enough. See https://nodejs.org/docs/latest/api/globals.html#globals_dirname (If you use __dirname inside a closure, it may be the path of the enclosing function.) For the near-term of "future", this doesn't look like it'll change, and will work as expected in all conditions -- whether the module is installed locally or globally, and whether others depend on the module or it's a direct install.
So let's assume the text file is in the same directory as the currently running script:
var fs = require('fs');
var path = require('path');
var dir = __dirname;
function runIt(cb) {
var fullPath = path.combine(__dirname, 'myfile.txt');
fs.readFile(fullPath, 'utf8' , function (e,content) {
if (e) {
return cb(e);
}
// content now has the contents of the file
cb(content);
}
}
module.exports = runIt;
Sweet!