webpack.config.js

const path = require('path');
const webpack = require('webpack');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

process.env.NODE_ENV = process.env.NODE_ENV || 'development';

if(process.env.NODE_ENV === 'development' ){
    require('dotenv').config({ path: '.env.development' });
}


module.exports = (env) => {
    const isProduction = env.production === true;
    return {
        entry: './src/app.js',
        output: {
            path: path.join(__dirname, 'public'),
            filename: 'bundle.js'
        },
        plugins: [
            new MiniCssExtractPlugin(),
            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_PROJECT_ID': JSON.stringify(process.env.FIREBASE_PROJECT_ID),
                'process.env.FIREBASE_STORAGE_BUCKET': JSON.stringify(process.env.FIREBASE_STORAGE_BUCKET),
                'process.env.FIREBASE_MESSAGING_SENDER_ID': JSON.stringify(process.env.FIREBASE_MESSAGING_SENDER_ID),
                'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL)
            })
        ],
        module: {
            rules: [
                {
                    loader: 'babel-loader',
                    test: /\.js$/,
                    exclude: /node_modules/
                },
                {
                    test: /\.s?css$/,
                    use: [
                        MiniCssExtractPlugin.loader, 
                        {
                            loader: 'css-loader',
                            options: {
                                sourceMap: true
                            }
                        },
                        {
                            loader: 'sass-loader',
                            options: {
                                sourceMap: true
                            }
                        },
                    ]
                },
                {
                    test: /\.(jpg|png|svg)$/,
                    use: {
                      loader: 'url-loader',
                    },
                },
            ]
        },
        devtool: isProduction ? 'source-map' : 'inline-source-map',
        devServer: {
            contentBase: path.join(__dirname, 'public'),
            historyApiFallback: true
        }
    }
};