Example of webpack configuration with Vue and Babel. Takes too much time (~50s).

webpack.config.babel.js

import webpack from 'webpack';
import path from 'path';
import ExtractTextPlugin from 'extract-text-webpack-plugin';
import postcssImport from 'postcss-import';
import pxtorem from 'postcss-pxtorem';
import cssnext from 'postcss-cssnext';
import postcssNesting from 'postcss-nesting';
import postcssVariables from 'postcss-variables';
import postcssColorFn from 'postcss-color-function';
import cssnano from 'cssnano';

export default {
  entry: {
    bundle: './src/ui/main'
  },
  output: {
    path: './assets',
    filename: 'js/[name].min.js'
  },
  module: {
    rules: [
      {
        test: /\.js?/,
        use: [
          {
            loader: 'babel-loader',
            options: {
              presets: [ [ 'es2015', { modules: false } ]]
            }
          }
        ],
        exclude: [/node_modules/]
      },
      {
        test: /particles\.js/,
        use: [
          {
            loader: 'exports-loader',
            options: {
              particlesJS: 'window.particlesJS,pJSDom: window.pJSDom'
            }
          }
        ]
      },
      {
        test: /\.css?/,
        use: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: [
            {
              loader: 'css-loader'
            },
            {
              loader: 'postcss-loader',
              options: {
                plugins: () => [
                  postcssImport({
                    //addDependencyTo: w
                  }),
                  cssnext({
                    warnForDuplicates: false
                  }),
                  pxtorem({
                    rootValue: 16,
                    unitPrecision: 5,
                    mediaQuery: true,
                    propList: ['*']
                  }),
                  postcssVariables,
                  postcssColorFn,
                  postcssNesting,
                  cssnano({ zIndex: false })
                ]
              }
            }
          ]
        })
      },
      {
        test: /\.(jpe?g|png|gif|svg)$/i,
        use: [
          {
            loader: 'file-loader',
            options: {
              hash: 'sha512',
              digest: 'hex',
              name: '[hash].[ext]'
            }
          },
          {
            loader: 'image-webpack-loader',
            options: {
              bypassOnDebug: true,
              optimizationLevel: 7,
              interlaced: false
            }
          }
        ]
      },
      {
        test: /\.vue?/,
        loader: 'vue-loader'
      }
    ]
  },
  resolve: {
    modules: [
      path.resolve('/'),
      'node_modules/'
    ],
    extensions: ['.js', '.vue'],
    unsafeCache: true
  },
  plugins: [
    new webpack.ProvidePlugin({
      Promise: 'imports-loader?this=>global!exports-loader?global.Promise!es6-promise',
      fetch: 'imports-loader?this=>global!exports-loader?global.fetch!whatwg-fetch',
    }),
    new webpack.optimize.UglifyJsPlugin(),
    new ExtractTextPlugin('css/[name].min.css')
  ],
  devtool: 'source-map',
  stats: { colors: true },
  watch: true
};