webpack.config.js

const defaultConfig = require( '@wordpress/scripts/config/webpack.config' );
const MiniCssExtractPlugin = require( 'mini-css-extract-plugin' );
const path = require( 'path' );
const glob = require( 'glob' );
const entries = {};

const production = process.env.NODE_ENV === '';

const processPostCss = ( folder, prefix ) => {
	glob.sync( `assets/entry/css/${ folder }/${ prefix }*.pcss` ).forEach(
		( filePath ) => {
			const fileName = path.basename( filePath, '.pcss' );
			// eslint-disable-next-line no-undef
			entries[ `css/${ folder }/${ fileName }` ] = path.resolve(
				process.cwd(),
				filePath
			);
		}
	);
};
processPostCss( 'frontend/blocks', 'core-' );
processPostCss( 'frontend', 'front-' );
processPostCss( 'backend/editor', '' );

// array of file name:
module.exports = [
	{
		...defaultConfig,
		optimization: {
			minimize: true,
		},
		module: {
			...defaultConfig.module,
			rules: [
				...defaultConfig.module.rules,
				{
					test: /\.pcss$/i,
					use: [
						MiniCssExtractPlugin.loader,
						'css-loader',
						{
							loader: 'postcss-loader',
							options: {
								postcssOptions: {
									config: path.resolve(
										__dirname,
										'postcss.config.js'
									),
								},
							},
						},
					],
				},
				{
					test: /\.js$/,
					exclude: /\/lib\//,
					use: [
						{
							loader: 'babel-loader',
							options: {
								presets: [ '@babel/preset-env' ],
								plugins: [
									'@babel/plugin-proposal-class-properties',
									'@babel/plugin-transform-runtime',
								],
							},
						},
					],
				},
				{
					test: /\.ts?$/,
					use: [
						{
							loader: 'ts-loader',
							options: {
								configFile: 'tsconfig.json',
								transpileOnly: true,
							},
						},
					],
				},
			],
		},

		plugins: [
			...defaultConfig.plugins,
			new MiniCssExtractPlugin( {
				filename: '[name].css',
				ignoreOrder: true,
			} ),
		],

		entry: entries,
		output: {
			filename: '[name].js',
			path: path.resolve( __dirname, './assets/bundle' ),
		},
	},
];

if ( production ) {
	module.exports.devtool = false;
}