webpack.dev.js

const path = require('path');
const webpack = require('webpack');
const { merge } = require('webpack-merge');
const webpackCommon = require('./webpack.common');

module.exports = merge(webpackCommon, {
  mode: 'development',
  devtool: 'inline-source-map',
  target: 'web',
  devServer: {
    port: 3300,
    watchContentBase: true,
    contentBase: path.resolve(__dirname, 'build'),
    publicPath: '/',
    historyApiFallback: true,
    compress: true,
    hot: true,
    open: true,
  },
  module: {
    rules: [
      {
        test: /\.css$/,
        include: /stylesheets|node_modules|src/,
        use: [
          'style-loader',
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1,
            },
          },
          { loader: 'postcss-loader', options: { sourceMap: true } },
        ],
      },
    ],
  },
  plugins: [new webpack.HotModuleReplacementPlugin()],
});