webpack.dev.js

const path = require("path");
const common = require("./webpack.common");
const merge = require("webpack-merge");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const CleanWebpackPlugin = require("clean-webpack-plugin");
const HtmlWebPackPlugin = require("html-webpack-plugin");

module.exports = merge(common, {
  mode: "development",
  output: {
    filename: "js/[name].[contentHash].bundle.js",
    path: path.resolve(__dirname, "dist")
  },
  module: {
    rules: [
      {
        test: /\.(scss|css)$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader
          },
          {
            loader: "css-loader"
          },
          {
            loader: "sass-loader"
          }
        ]
      }
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      // options similar to the same options in webpackOptions.output
      // Both options are optional
      filename: "css/[name].[contentHash].css",
      chunkFilename: "[id].css"
    }),
    new CleanWebpackPlugin(),
    new HtmlWebPackPlugin({
      template: "./src/index.html"
    })
  ]
});