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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;

How do I open a file saved in the user directory using Electron's Shell API

I'd like an Electron app to natively open a file stored in the User directory, with the path as %userprofile%/Documents/Dir1/ThisFile.txt.
From Electron's Shell Documentation:
const { shell } = require('electron')
shell.openPath('%userprofile%/Documents/Dir1/ThisFile.txt')
yields an error:
Windows cannot find '%userprofile%/Documents/Dir1/ThisFile.txt'. Make sure you typed the name correctly and try again.
I have also tried using:
shell.openPath(path.relative('./','%userprofile%/Documents/Dir1/ThisFile.txt')); which results in the same error.
What am I doing wrong? Is there a way to open a file stored in %userprofile%.

Use electron's cross-platform .getPath() method for that:
const path = require("path");
const { app, shell } = require("electron");
shell.openPath(path.join(app.getPath("documents"), "Dir1", "ThisFile.txt"));
See here: https://www.electronjs.org/docs/api/app#appgetpathname

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!

How to probe if a file was download using Selenium/WebdriverIO

I want to know how I can verify if a file was downloaded using Selenium Webdriver after I click the download button.

Your question doesn't say whether you want to confirm it locally or remotely(like browserstack) . If it is remotely then my answer will be "NO" as you can see that the file is getting downloaded but you can not access the folder. So you wont be able to assert that the file has been downloaded.
If you want to achieve this locally(in Chrome) then the answer is "YES", you can do it something like this:
In wdio.conf.js(To know where it is getting downloaded)
var path = require('path');
const pathToDownload = path.resolve('chromeDownloads');
// chromeDownloads above is the name of the folder in the root directory
exports.config = {
capabilities: [{
maxInstances: 1,
browserName: 'chrome',
os: 'Windows',
chromeOptions: {
args: [
'user-data-dir=./chrome/user-data',
],
prefs: {
"download.default_directory": pathToDownload,
}
}
}],
And your spec file(To check if the file is downloaded or not ?)
const fsExtra = require('fs-extra');
const pathToChromeDownloads = './chromeDownloads';
describe('User can download and verify a file', () =>{
before(() => {
// Clean up the chromeDownloads folder and create a fresh one
fsExtra.removeSync(pathToChromeDownloads);
fsExtra.mkdirsSync(pathToChromeDownloads);
});
it('Download the file', () =>{
// Code to download
});
it('Verify the file is downloaded', () =>{
// Code to verify
// Get the name of file and assert it with the expected name
});
});
more about fs-extra : https://www.npmjs.com/package/fs-extra
Hope this helps.

TL;DR: Unless your web-app has some kind of visual/GUI trigger once the download finishes (some text, an image/icon-font, push-notification, etc.), then the answer is a resounding NO.
Webdriver can't go outside the scope of your browser, but your underlying framework can. Especially if you're using NodeJS. :)
Off the top of my head I can think of a few ways I've been able to do this in the past. Choose as applicable:
1. Verify if the file has been downloaded using Node's File System (aka fs)
Since you're running WebdriverIO, under a NodeJS environment, then you can make use its powerful lib tool-suite. I would use fs.exists, or fs.existsSync to verify if the file is in the expected folder.
If you want to be diligent, then also use fs.statSync in conjunction with fs.exists & poll the file until it has the expected size (e.g.: > 2560 bytes)
There are multiple examples online that can help you put together such a script. Use the fs documentation, but other resources as well. Lastly, you can add said script inside your it/describe statement (I remember your were using Mocha).
2. Use child_process's exec command to launch third-party scripts
Though this method requires more work to setup, I find it more relevant on the long run.
!!! Caution: Apart from launching the script, you need to write a script in a third-party framework.
Using an AutoIT script;
Using a Sikuli script;
Using a TestComplete (not linking it, I don't like it that much), or [insert GUI verification script here] script;
Note: All the above frameworks can generate an .exe file that you can trigger from your WebdriverIO test-cases in order to check if your file has been downloaded, or not.
Steps to take:
create one of the stand-alone scripts like mentioned above;
place the script's .exe file inside your project in a known folder;
use child_process.exec to launch the script and assert its result after it finishes its execution;
Example:
exec = require('child_process').exec;
// Make sure you also remove the .exe from scriptName
var yourScript = pathToScript + scriptName;
var child = exec(yourScript);
child.on('close', function (code, signal) {
if (code!==0) {
callback.fail(online.online[module][code]);
} else {
callback();
}
});
Finally: I'm sure there are other ways to do it. But, your main take-away from such a vague question should be: YES, you can verify if the file has been downloaded if you absolutely must, expecially if this test-case is CRITICAL to your regression-run.

Nodejs Browserify Uncaught TypeError: exists is not a function

I am new to Browserify and trying the following:
I created a node server and trying to get a package called 'openbci' running on the browser.
so I have the following file structure:
Myapp
-...
-public
--app.js
--index.html
--openBCI.js
--...
--javascript
---openBCI
----bundle.js
---...
-node_modules
--openbci
---openBCIBoard.js
--browserify
--...
my app.js file sets the server to serve the public folder
// app.js
var express = require('express');
var app = express();
app.use(express.static('public'));
app.listen(myPort);
then I created the following openBCI.js
// openBCI.js
var OpenBCIBoard = require('openbci').OpenBCIBoard;
exports.OpenBCIBoard = OpenBCIBoard;
and finally launched the browserify command:
$ browserify public/openBCI.js > public/javascript/openBCI/bundle.js
but once called in my index.html file, I got an Uncaught TypeError: exists is not a function at Function.getRoot:
exports.getRoot = function getRoot (file) {
var dir = dirname(file)
, prev
while (true) {
if (dir === '.') {
// Avoids an infinite loop in rare cases, like the REPL
dir = process.cwd()
}
**if (exists(join(dir, 'package.json')) || exists(join(dir, 'node_modules'))) {**
// Found the 'package.json' file or 'node_modules' dir; we're done
return dir
}
if (prev === dir) {
// Got to the top
throw new Error('Could not find module root given file: "' + file
+ '". Do you have a `package.json` file? ')
}
// Try the parent dir next
prev = dir
dir = join(dir, '..')
}
}
It appears that it could not find the original path for the module.
Could you please tell me what is to change? Or if I understood at all how browserify works ? :)

I notice a few things that seem strange about the code.
exists is undefined in JavaScript or node. It appears to be an alias of fs.exists - is that right?
If so, fs.exists is deprecated. Per the documentation, you can achieve the same effect with fs.stat or fs.access. Note however that you should either supply a callback (preferable) or use the Sync version of these methods.
If you are trying to use file system tools in the browser you are going to run into problems because you are attempting to access the server's file system from the browser. There is a plugin, browserify-fs, that gives you an equivalent to fs in the browser. However, this seems to access the browser's local IndexedDB, not the storage on your server.
I would suggest running code that relies on server-side files on the server, rather than in the browser.