webpack.prod.js

const merge             = require('webpack-merge');
const common            = require('./webpack.common.js');
const UglifyJsPlugin    = require('uglifyjs-webpack-plugin');
const ExtractTextPlugin = require("extract-text-webpack-plugin");

module.exports = merge(common, {
    module: {
        rules: [
            {
                test: /\.scss/,
                use: ExtractTextPlugin.extract({
                    fallback: 'style-loader',
                    use: [{
                        loader: 'css-loader',
                        options: {
                            minimize: true
                        }
                    }, {
                        loader: 'postcss-loader'
                    }, {
                        loader: 'sass-loader'
                    }]
                })
            }
        ]
    },
    plugins: [
        new UglifyJsPlugin({
            uglifyOptions: {
                compress: {
                    drop_console: true
                },
                output: {
                    comments: false,
                }
            }
        })
    ]
});