Sample preact.config.js with wepback modifications

preact.config.js

/**
 * Function that mutates original webpack config.
 * Supports asynchronous changes when promise is returned.
 *
 * @param {object} config - original webpack config.
 * @param {object} env - options passed to CLI.
 * @param {WebpackConfigHelpers} helpers - object with useful helpers when working with config.
 **/
import AggressiveMergingPlugin from "./node_modules/webpack/lib/optimize/AggressiveMergingPlugin";
import CompressionPlugin from "compression-webpack-plugin";

export default function (config, env, helpers) {
    // config.resolve.alias['framework7$'] = 'framework7/dist/framework7.esm.bundle';
    /** you can change config here **/
    if (env.isProd) {
        const uglifyDesc = helpers.getPluginsByName(config, 'UglifyJsPlugin').pop();
        config.plugins.splice(uglifyDesc.index + 1, 0, new AggressiveMergingPlugin());
        config.plugins.splice(uglifyDesc.index + 2, 0, new CompressionPlugin({
            asset: "[path].gz[query]",
            algorithm: "gzip",
            test: /\.js$|\.css$|\.html$/,
            threshold: 10240,
            minRatio: 0.8
        }));
    }
}