how to bild a react app in npm code example

Example 1: create react app install

RUN IN CMD

npm install -g create-react-app

Example 2: build react app

Build a react project
Code has to be bundled using a bundler like webpack and
 transformed using a compiler like Babel.
do production optimizations such as code splitting(critical CSS)
statically pre-render some pages for performance and SEO. 
use server-side rendering or client-side rendering.
write some server-side code to connect your React app to your data store.
OR use create-react-app