React JS

One of the popular JavaScript libraries, React.js specializes in UIs but is most useful for constructing definite UIs for single-page applications. It makes interactive and dynamic user interfaces with reusable components.

Components represent the different building blocks of the React application. It defines what a portion of UI should look like and how it should behave through independent and reusable chunks of code.

JSX stands for JavaScript XML. It is a syntax extension that allows you to write HTML-style elements directly in JavaScript. Now you will have your code written without any difficulty in understanding it through HTML and JavaScript together in one place.

The state is made for storing information that is likely to change with time, leading to some behavioral change within the component. On the other hand, props are those values that are transferred from parent components to child components to share information.

Different lifecycle phases of a React component, such as that of being newly created and mounted, updated, or unmounted, have methods that react to those differences concerning the particular phase of the component's life.

Used primarily for routing in React applications, React Router allows the user to navigate between components and pages without refreshing the page, which allows a smooth UX mostly in single-page applications.

Using a very tiny copy of the actual DOM, React uses updates in virtual DOOM, that is, in the parts of the UI that have changed so that nothing will be disturbed on the entire page re-rendering.

Hooks are functions that enable ordinary functions to use React state as well as lifecycle functions, thus providing a more robust way of creating reusable and cleaner code.

Redux is a state management library mostly used to govern the application state predictably. It works with React by making a centralized storage location through which to store the application state, thus making it easy to manage and pass data between the components.

In React, forms are usually managed by using controlled components, meaning that the data contained in the form will be learned from the component's state, and any change to the input field will change the state, thus making it easy to validate and submit forms.