Example webpack.config.js file for extending wp-scripts build.

webpack.config.js

/**
 * External Dependencies
 */
const path = require('path');

/**
 * WordPress Dependencies
 */
const defaultConfig = require('@wordpress/scripts/config/webpack.config.js');

module.exports = {
	...defaultConfig,
	...{
		entry: {
			'admin-scripts': path.resolve(process.cwd(), 'src', 'admin.js'),
			'public-scripts': path.resolve(process.cwd(), 'src', 'public.js'),
		},
	},
};