Is React JS frontend or backend?

React is a JavaScript library for building user interfaces, typically used for building front-end (client-side) web applications.

What is the model in AngularJS?

In an application using MVC architecture, the model is responsible for both representing the data displayed in the view and handling user interactions such as button clicks, scrolling, and other changes in the view. In AngularJS, the $scope object acts as the model in simpler applications, and the ng-model directive binds the values of HTML controls, such as input, select, and text area, to the data in the application.