Webpack Dev Server: Unknown argument: NODE_ENV - npm

Question

I have setup my angular js project with webpack. I am getting below error whenever I try to run in development mode:
"Unknown argument: NODE_ENV".
Below is my package.json. I am already using latest version of webpack-dev-server. Please let me know what went wrong here.
Package.json:
{
"name": "My project",
"version": "0.0.1",
"description": "",
"main": "/",
"author": "",
"license": "MIT",
"scripts": {
"start": "webpack-dev-server --config webpack/webpack.dev.js --watch --NODE_ENV=dev",
"test": "karma start --NODE_ENV=test",
"build": "webpack --config webpack/webpack.build.js --NODE_ENV=production"
},
"dependencies": {
"angular": "1.6.3",
"angular-datepicker": "^1.0.5",
"angular-file-upload": "^2.2.0",
"angular-flash-alert": "^2.2.4",
"angular-messages": "^1.5.0",
"angular-repository": "^0.1.8",
"angular-resource": "^1.5.0",
"angular-sanitize": "^1.5.5",
"angular-symfony-acl": "^1.0.9",
"angular-symfony-form": "^3.0.0",
"angular-translate": "^2.11.0",
"angular-ui-bootstrap": "^1.3.2",
"angular-ui-router": "^0.2.18",
"angular-voauth2": "^0.1.16",
"angular-youtube-embed": "^1.2.0",
"angularjs-datepicker": "^2.1.3",
"bootstrap": "^3.3.6",
"bootstrap-sass": "3.3.6",
"dotenv": "^4.0.0",
"font-awesome": "4.5.0",
"jquery": "2.2.0",
"lodash": "^4.0.1",
"moment": "^2.12.0",
"ng-file-upload": "^12.0.4",
"ng-infinite-scroll": "^1.2.1",
"postcss-loader": "^0.9.1",
"ui-select": "^0.19.4"
},
"devDependencies": {
"angular-mocks": "1.5.0-rc.2",
"angular-module-mocks": "1.2.19",
"babel-core": "^6.4.5",
"babel-istanbul": "0.6.0",
"babel-loader": "^6.2.4",
"babel-preset-es2015": "^6.3.13",
"compression-webpack-plugin": "0.3.0",
"connect-history-api-fallback": "^1.2.0",
"css-loader": "^0.18.0",
"file-loader": "0.8.5",
"html-webpack-plugin": "2.7.2",
"webpack-dev-server": "2.4.2",
"istanbul": "0.4.2",
"istanbul-instrumenter-loader": "0.1.3",
"jasmine": "2.4.1",
"karma": "0.13.19",
"karma-coverage": "0.5.3",
"karma-jasmine": "0.3.6",
"karma-phantomjs-launcher": "1.0.0",
"karma-sourcemap-loader": "0.3.7",
"karma-spec-reporter": "0.0.23",
"karma-typescript-preprocessor": "0.0.21",
"karma-webpack": "1.7.0",
"lodash": "4.0.1",
"node-sass": "3.4.2",
"phantomjs-polyfill": "0.0.1",
"phantomjs-prebuilt": "2.1.3",
"raw-loader": "0.5.1",
"sass-loader": "3.1.2",
"style-loader": "0.13.0",
"url-loader": "0.5.7",
"webpack": "1.12.12"
}
}
webpack.dev.js:
var loaders = require("./loaders");
var webpack = require('webpack');
var HtmlWebpackPlugin = require('html-webpack-plugin');
module.exports = {
entry: {
build: './src/app.js',
vendors: ['angular', 'bootstrap', 'angular-ui-router', 'ng-file-upload']
},
output: {
filename: '[name].min.js',
path: 'dist'
},
resolve: {
root: __dirname,
extensions: ['', '.js', '.json']
},
resolveLoader: {
modulesDirectories: ["node_modules"]
},
devtool: "source-map",
devServer: {
port: 8080,
historyApiFallback: true
},
plugins: [
new HtmlWebpackPlugin({
template: './src/index.html',
inject: 'body',
hash: true
}),
new webpack.ProvidePlugin({
moment: 'moment',
$: 'jquery',
jQuery: 'jquery',
'window.jQuery': 'jquery',
'window.jquery': 'jquery'
})
],
module:{
loaders: loaders
}
};

Answer 1

In addition to what #Emre has provided, I had to change the npm start command in package.json to run application in DEV MODE. Then only it worked for me. My package.json now looks as below:
"scripts": {
"start": "NODE_ENV=dev webpack-dev-server --config ./webpack/webpack.dev.js --",
"test": "karma start --NODE_ENV=test",
"build": "webpack --config webpack/webpack.build.js --NODE_ENV=production"
},
Thanks.

Answer 2

You need to define your NODE_ENV in your wepack configuration. This should work:
plugins: [
new webpack.DefinePlugin({
"process.env": {
NODE_ENV: JSON.stringify(process.env.NODE_ENV || 'production') // default value if not specified
}
})
]