webpack.config.js

var path = require("path");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
var OptimizeCssAssetsPlugin = require("optimize-css-assets-webpack-plugin");

module.exports = {
  entry: {
    materialize: "./assets/src/js/materialize.js",
    _smaterialize: "./assets/src/js/index.js",
    "_smaterialize-editor": "./assets/src/js/gutenberg.js"
  },
  output: {
    filename: "[name].js",
    path: path.resolve(__dirname, "./assets/dist/js")
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader"
        }
      },
      {
        test: /\.(png|jpg|gif|svg|eot|ttf|woff|woff2)$/,
        loader: "url-loader",
        options: {
          limit: 10000
        }
      },
      {
        test: /\.s?[ac]ss$/,
        use: [
          MiniCssExtractPlugin.loader,
          {
            loader: "css-loader",
            options: {
              importLoaders: 2,
              sourceMap: true
            }
          },
          {
            loader: "postcss-loader",
            options: {
              sourceMap: true
            }
          },
          {
            loader: "resolve-url-loader",
            options: {
              debug: true
            }
          },
          {
            loader: "sass-loader",
            options: {
              sourceMap: true,
              sourceMapContents: false
            }
          }
        ]
      }
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: "../../../assets/dist/css/[name].css"
    }),
    new OptimizeCssAssetsPlugin({
      assetNameRegExp: /\.css$/g,
      cssProcessor: require("cssnano"),
      cssProcessorPluginOptions: {
        preset: ["default", { discardComments: { removeAll: true } }]
      },
      canPrint: true
    })
  ]
};