Node.js - NODE_ENV is undefined - node.js

Question

I am trying to set the environment variable NODE_ENV for my project.
I am using Windows and have set the NODE_ENV in the system settings - this has been verified by typing SET and identifying for the row below in the output.
NODE_ENV=production
I cannot seem to get the variable to set in webpack though.
When adding the code below to my project (index.js) it only logs out undefined
console.log('PROCESS', process.env.NODE_ENV)
My webpack config:
const path = require('path');
const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin')
process.env.NODE_ENV = process.env.NODE_ENV || 'development'
if (process.env.NODE_ENV === 'test') {
require('dotenv').config({ path: '.env.test' })
} else if (process.env.NODE_ENV === 'development') {
require('dotenv').config({ path: '.env.development' })
} else if (process.env.NODE_ENV === 'production') {
require('dotenv').config({ path: '.env.production' })
} else {
require('dotenv').config({ path: '.env.development' })
}
module.exports = (env) => {
const isProduction = env === 'production';
...
plugins: [
CSSExtract,
new UglifyJSPlugin(),
new webpack.DefinePlugin({
'process.env.FIREBASE_API_KEY': JSON.stringify(process.env.FIREBASE_API_KEY),
'process.env.FIREBASE_AUTH_DOMAIN': JSON.stringify(process.env.FIREBASE_AUTH_DOMAIN),
'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL),
...
}),
devtool: isProduction ? 'source-map' : 'inline-source-map',
...
I have read this question, but still cannot get the env variable to set.
Where am I going wrong?

Answer 1

I managed to get set the NODE_ENV by using the cross-env package!
If you are developing node.js on Windows this can be very useful. Linux/Mac users would not have this problem.
To set the environment variable simply type
cross-env NODE_ENV=production [your commend goes here]
Example:
cross-env NODE_ENV=production webpack --env production