webpack.config.js

var path = require('path');
var webpack = require('webpack');

function getEntrySources(sources) {
  if (process.env.NODE_ENV !== 'production') {
    sources.push('webpack-dev-server/client?http://localhost:8080');
    sources.push('webpack/hot/only-dev-server');
  }

  return sources;
}

module.exports = {
  devtool: process.env.NODE_ENV !== 'production' ? 'eval-source-map' : '',
  entry: {
    bundle: getEntrySources(['./src/app.js'])
  },
  output: {
    publicPath: 'http://localhost:8080/',
    filename: 'dist/[name].js'
  },
  plugins: process.env.NODE_ENV !== 'production' ?
    [] :
    [
      new webpack.optimize.OccurenceOrderPlugin(),
      new webpack.DefinePlugin({
        'process.env': {
          'NODE_ENV': JSON.stringify('production')
        }
      }),
      new webpack.optimize.UglifyJsPlugin({
        compressor: {
          warnings: false
        }
      })
    ],
  module: {
    preLoaders: [{
      test: /\.js$/,
      loader: 'source-map-loader'
    }],
    loaders: [{
      test: /\.css$/,
      loader: 'style-loader!css-loader!postcss-loader!cssnext-loader'
    }, {
      test: /\.js$/,
      loaders: ['react-hot', 'babel-loader?stage=0', 'eslint-loader'],
      exclude: /node_modules/
    }, {
      test: /\.json$/,
      loader: 'json-loader'
    }, {
      test: /\.(png|jpg|jpeg|gif|svg)$/,
      loader: 'url-loader?prefix=img/&limit=5000'
    }, {
      test: /\.woff(2)?(\?v=[0-9]\.[0-9]\.[0-9])?$/,
      loader: 'url-loader'
    }, {
      test: /\.(ttf|eot|svg)(\?v=[0-9]\.[0-9]\.[0-9])?$/,
      loader: 'file-loader'
    }]
  }
};