This demo is to understand how "ReactReduxContext.Consumer" works.
npm install
npm run demo
I type in the text field, but nothing happens, how to make it work?
https://stackoverflow.com/questions/60707502/how-is-reactreduxcontext-consumer-working/60707655
ReactReduxContext.Consumer should be just give us a way to get the store without getting it globally.
When state of store changes, our component will be re-rendered automatically,
we have to manually render them like using store.subscribe