Check out following links that demonstrates different concepts with code and screenshot. In the project's readme, instructions to install the project and get it runnning are given.

How to create REST API using nodejs, mongoose, expressjs

Employee Management Application Using React

Infinite Scroll example using React. How to consume the API and display restaurants data using infinite scroll.

How to create form in react and how to validate the form and display validation errors in React

CRUD example using React. Screenshots attached

How to create REST API using Golang, Gorm and MySql

Demonstration of how to use Semanti UI React Modal