A little bit of soft touch on the the server rendering using Reactjs, webpack and ExpressJs going through the execution of this project:
npm install -g webpack
webpack
and then use the defined loader to transpile js 'ES6' file into that which would be understood by the browser.
---- webpack --watch.
Then on the other command prompt: just run:
node app.js
nodemon app.js
(more on this last command... check out the package.json)