text: var webpack = require('webpack');
  var merge = require('webpack-merge');
  
  var baseConfig = require('./webpack.base.config');
  var optimizationConfig = require('./webpack.opt.config');
  
  const productionConfiguration = function (env) {
    const NODE_ENV = env.NODE_ENV ? env.NODE_ENV : 'development';
    return {
      plugins: [
        new webpack.DefinePlugin({ 'process.env.NODE_ENV': JSON.stringify(NODE_ENV) }),
      ]
    };
  }
  
  module.exports = merge.smart(baseConfig, optimizationConfig, productionConfiguration);
  