webpack.config.js

const webpack = require('webpack')
const Configs = require('react-project/webpack')

Configs.ServerConfig.module.loaders.unshift({
  test: /modules\/client-only\//,
  loader: 'null-loader'
})

Configs.ClientConfig.plugins.push(
  new webpack.ContextReplacementPlugin(/moment[\/\\]locale$/, /en/)
)

Configs.ClientConfig.module.loaders.forEach((def) => {
  if (def.loader.match(/style-loader/)) {
    def.exclude= /modules\/syntax\.css$/
  }

  if (def.test.test('jpg')) {
    def.loader = 'url-loader?limit=10000!img-loader?progressive=true'
  }
})

Configs.ClientConfig.module.loaders.push({
  test: /modules\/syntax\.css$/,
  loader: 'style-loader!css-loader'
})

module.exports = Configs

Is this a package or a file you have created it if so can you share it please
'react-project/webpack'