webpack.config.js

const path = require('path');
const nodeExternals = require('webpack-node-externals');

/**
 * Determine wether or not is the production build.
 * @type {Boolean}
 */
const isBuild = process.env.npm_lifecycle_event === 'build';

module.exports = {
    entry: './src/index.js',

    output: {
        path: path.resolve(__dirname, 'build'),
        filename: 'index.js',
        libraryTarget: 'commonjs2',
    },

    module: {
        noParse: /(mapbox-gl)\.js$/,
        rules: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                use: { loader: 'babel-loader' },
            },
            {
                test: /\.css$/,
                use: [{ loader: 'style-loader' }, { loader: 'css-loader' }],
            },
        ],
    },

    mode: isBuild ? 'production' : 'development',

    resolve: {
        extensions: ['.js', '.jsx'],
        modules: ['node_modules', './src'],
    },

    externals: [
        nodeExternals({
            allowlist: [/mapbox-gl\/dist\/mapbox-gl.css/],
        }),
    ],
};