webpack.config.js

const TerserPlugin = require('terser-webpack-plugin');
const path = require('path');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const FixStyleOnlyEntriesPlugin = require("webpack-fix-style-only-entries");
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');

module.exports = {
    entry: {
        'wcms-admin': './wcms-admin.js',
        styles: './wcms-admin.css',
    },
    optimization: {
        minimize: true,
        minimizer: [new TerserPlugin(), new OptimizeCSSAssetsPlugin({})],
    },
    output: {
        filename: '[name].min.js',
        path: path.resolve(__dirname, './'),
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [MiniCssExtractPlugin.loader, "css-loader"]
            }
        ]
    },
    plugins: [
        new MiniCssExtractPlugin({filename: "wcms-admin.min.css"}),
        new FixStyleOnlyEntriesPlugin(),
    ]
};