React

React (https://reactjs.org) is not a full-fledged MVVM framework. It is a JavaScript library for building client-side views or user interfaces. It is developed and backed by Facebook and has a vibrant community and ecosystem behind it. React follows an HTML in JS approach and has a special format called JSX to help us write React components. Unlike Angular, React doesn't have too many concepts or APIs to learn and hence is easier to start with, but React only cares about rendering the UI and hence to get similar functionality offered by Angular, we would have to pair React with other libraries like React Router (https://reacttraining.com/react-router), Redux (https://redux.js.org), MobX (https://mobx.js.org), and so on. JHipster uses React along with Redux and React Router and similar to Angular, JHipster uses TypeScript for React as well. But this is optional as React can be written using JavaScript as well, preferably ES6 (http://es6-features.org). React is fast to render due to its use of a virtual DOM (https://reactjs.org/docs/faq-internals.html) to manipulate a view instead of using the actual browser DOM.

If you are starting a new project, it is best to choose either Angular or React as they are well maintained. However, with older versions of JHipster, AngularJS 1.x was also offered as an option but it is becoming legacy and will soon be discontinued in JHipster 5.x. JHipster will provide an official blueprint for those who are still interested in using AngularJS 1.x. Just run the command jhipster --blueprint generator-jhipster-angularjs to use it.