Webpack config with external AMD module

webpack.config.js

const CleanWebpackPlugin = require('clean-webpack-plugin');
const HtmlPlugin = require('html-webpack-plugin');
const path = require('path');
const basePath = process.cwd();

module.exports = (env) => {
	return {
		externals: [
			function (context, request, callback) {
				if (request === 'some/amd/dep') {
					return callback(null, 'amd some/amd/dep');
				}
				callback();
			}
		],
		entry: {
			main: './src/main'
		},
		output: {
			path: path.resolve(basePath, 'dist'),
			filename: '[name].js',
			libraryTarget: 'umd'
		},
		resolve: {
			modules: [ 'node_modules' ]
		},
		plugins: [
			new CleanWebpackPlugin([ 'dist' ]),
			new HtmlPlugin({
				title: 'Sandbox'
			})
		]
	};
};