webpack.dev.js

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

module.exports = merge(common, {
  mode: 'development',
  devtool: 'inline-source-map',
  module: {
    rules: [
      {
        test: /\.html$/,
        use: [
          {
            loader: 'html-loader'
          }
        ]
      },
      {
        test: /\.(sa|sc|c)ss$/,
        use: [
          'style-loader',
          {
            loader: 'css-loader',
            options: {
              sourceMap: true
            }
          },
          {
            loader: 'postcss-loader',
            options: {
              sourceMap: true
            }
          },
          {
            loader: 'sass-loader',
            options: {
              sourceMap: true
            }
          }
        ]
      }
    ]
  },
  output: {
    filename: '[name].js',
    path: path.resolve(__dirname, 'dist')
  }
});