webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");

module.exports = {
  entry: ["@babel/polyfill", "./src/js/index.js"],
  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "js/bundle.js"
  },
  devServer: {
    contentBase: "./dist"
  },
  plugins: [
    new HtmlWebpackPlugin({
      filename: "index.html",
      template: "./src/index.html"
    })
  ],
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
          options: {
            presets: ["@babel/preset-env"]
          }
        }
      },
      {
        test: /\.scss$/,
        use: [
          "style-loader", // creates style nodes from JS strings
          "css-loader", // translates CSS into CommonJS
          "sass-loader" // compiles Sass to CSS, using Node Sass by default
        ]
      }
    ]
  }
};