webpack.config.js

var path = require('path')
var webpack = require('webpack')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')
// const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;

module.exports = {
    mode: 'development',
    entry: './src/index.js',
    output: {
        path: path.resolve(__dirname, './assets'),
        filename: 'app.js'
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: { presets: ['es2015', 'env', 'react'] }
                }
            },
            {
                test: /\.css$/,
                use: [ 'style-loader', 'css-loader' ]
            }
        ]
    },
    resolve: {
    },
    // devServer: {
    //     historyApiFallback: true,
    //     noInfo: true
    // },
    devtool: '#eval-source-map',
    plugins: [
        new webpack.HotModuleReplacementPlugin(),
        new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
    ]
}

if (process.env.NODE_ENV === 'production') {
    module.exports.devtool = '#source-map';
    module.exports.plugins = (module.exports.plugins || []).concat([
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: '"production"'
            }
        }),
        new webpack.optimize.OccurrenceOrderPlugin()
    ]);
    module.exports.optimization = {
        minimizer: [
            new UglifyJsPlugin()
        ]
    }
}