Unclear lesson 13. Follow up questions

[i-manolov]

Hey folks, why do we want the node modules to be retrieved at run time? Also why specifically concat react-dom/server and react/addons ? What is the purpose of declaring the file names as relative to the context in the node section? I apologize if those are noob questions.

It would be super helpful if those were explained in the tutorial.

  externals: fs.readdirSync(path.resolve(__dirname, 'node_modules')).concat([
    'react-dom/server', 'react/addons',
  ]).reduce(function (ext, mod) {
    ext[mod] = 'commonjs ' + mod
    return ext
  }, {}),

  node: {
    __filename: true,
    __dirname: true
  }