webpack.config.dev.js

const path = require('path');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = {
  resolve: { extensions: ['.js', '.jsx'] },
  entry: path.join(__dirname, 'lib', 'index.jsx'),
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'index.js',
    libraryTarget: 'umd'
  },
  mode: 'development',
  externals: {
    react: 'react'
  },
  module: {
    rules: [
      {
        test: /\.(jsx|js)?$/,
        loader: 'babel-loader',
        exclude: /(node_modules|bower_components)/
      }, {
        test: /(\.less|\.css)$/,
        use: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: [ 'css-loader', 'postcss-loader', 'less-loader'],
        }),
        // use: ['style-loader', 'css-loader']
      }
    ]
  },
  plugins: [
    new ExtractTextPlugin('index.css')
  ],
};