REACT JS CORE CONCEPTS

React Js is an open-source and free JavaScript library for building user interfaces (UI). This is one of the essential parts of MERN stack that is gaining attention of developers nowadays.

For building efficient, scalable and high-performance web applications using MERN stack, one must know about the core concepts. For front-end or MERN stack developer, the enough knowledge of the subsequent elements of the React is indispensable.

1. JSX

While designing frontend projects, we usually keep different files such as HTML, CSS and JavaScript codes in different files. But React works differently where we do not need HTML files. React offers JSX which is a syntax extension of JavaScript which enable you to code HTML in JavaScript syntax. This makes code more readable and provides ease in creating UI components.  Whenever you render the JSX element, this will be converted into the JavaScript objects that eventually make the DOM nodes.

2. Components

In React, we divide a front-end page or UI in different components. Component is a reusable piece of code which carries UI code. There are two classes of components: functional and class-based. Functional components are lightweight and simple functions which returns JSX discussed previously. However, class-based component is more robust and powerful that offers flexibility for advanced features such as lifecycle methods and states.

3. State

React introduces an interesting feature of state that contains information about the component. The state of a component keeps changing over time upon triggers such as fetched data, user input or system generated events. The dynamic data of component is carried out by this feature and can be accessed through setState() command.

4. Props

Props, derived from properties, are simply used to communicate between various components in React. Technically, they are used to pass the data from parent to child component. Props are particularly used for configuring the appearance and behavior of child components. Props are read only or immutable, meaning that these cannot be altered within child component.

5. Lifecycle Methods

React lifecycle methods are simply the events that take place from the birth of a React component to its death. These are the stages like when first mounted to DOM, unmounted or updated. Certain tasks such as cleaning resources or fetching data from API can be done through Lifecycle methods.

6. Virtual DOM

In react, virtual DOM is used to compute DOM operations minimally when the component is to be rendered. The props and state are changing frequently in React, so each time whenever changes occur, a new virtual DOM is created. Each time this virtual DOM is compared with the previous one and identify the changes that needs to be updated. This method is robust and fast than the conventional DOM manipulation due to minimizing the operations that are needed.

Conclusively, the core concepts of React has to be understood by React developer to build efficient and scalable web applications. By equipping with these concepts, developers can be capable of building user interfaces that can handle complex operations.