Top 20 React interview questions for fresher

 

Top 20 React interview questions for fresher

This tutorial will discuss the top 20 React questions related to the interview for freshers.

 React Interview Questions

The top 20 interview question based on the reactions of the fresher is as follows:

Question 1: What do you understand by React?

React is usually considered the front-end and the open-source JavaScript library that is useful in developing the UI (User interface) purposely for the applications with a single page. And also, React is quite helpful in building complex and reusable user interface (UI) components, particularly for mobile and web applications, as it also follows the component-based approach.

 

Questions 2: What are the various advantages of using React?

The various advantages of using the React are as follows:

·        Huge collection of libraries to choose from: React usually provides an individual with the freedom to choose the various tools, libraries, and architecture to develop the respective applications on the requirement of the respective individual.

·        Reusable components: React, in general, makes use of the component-based architecture to develop the applications. And the components are considered to be the independent and the reusable bits of code and can be shared across the various applications that usually have similar functionality.

·       Makes use of the Virtual DOM: React usually uses the virtual DOM to enhance the view. Virtual DOM means the virtual representation of the real DOM effectively.

 

Questions 3. What are the various limitations of using React?

The various limitations of using the React are as follows:

·        React is generally encapsulated with lots of components, and grasping the benefits of various components is quite time-consuming.

·        With the effective use of JSX and inline templating, coding has become complex.

·       React is only a library and cannot be considered a full-blown framework.

 

Questions 4: Differentiate between Real DOM and Virtual DOM?

Real DOM

Virtual DOM

 

·        Updation is quite slow.	·        Updation is quite faster.
·        HTML can be directly updated.	·        HTML cannot be directly updated.
·        Lots of memory wastage.	·        No memory wastage.
·        Manipulation by DOM is very expensive.	·        Manipulation by DOM is very easy.

 

Question 5: What is JSX?

JSX is usually considered to be the shorthand for JavaScript XML. This is the kind of file that can be used by React, which usually utilizes the expressiveness of JavaScript along with the HTML-like template syntax. This makes the HTML files quite easy to understand, makes them robust and helps effectively boost their performance.

 

Questions 6: Why browsers can't you read JSX?

Usually, browsers can only read JavaScript objects effectively. Still, considering the JSX, then, it is not a regular JavaScript object. Thus, to enable the browsers to read JSX, we first need to transform the JSX file into the JavaScript object.

 

Questions 7: What are Props?

Props are generally considered the shorthand for the Properties used in React. Moreover, they are considered the read-only components that must be kept in pure form and are passed down from the parent to the child components throughout the applications.

 

Questions 8: What is the state in React?

States are generally considered the heart of the React components, are the data source, and are defined to be kept as simple as possible. States are the objects that usually determine the rendering and behavior of a particular component.

 

Questions 9: What is the different phase of React component’s lifecycle?

In general, there are three different phases of React component's lifecycle:

1)     Initial rendering phase.

2)     Updating phase.

3)    Unmounting phase.

 

Questions 10: Differentiate between Angular and React?

The difference between the Angular and React is as follows:

Angular	React
·        Created by Google	·        Created by Facebook.
·        Angular is a Real DOM.	·        React is a Virtual DOM.
·        Angular is client-side.	·        React is server-side.
·        It has full MVC support.	·        It has only a view aspect of MVC.

 

Questions 11: What are the advantages of using create-react-app CLI?

The various advantages of using the create-react-app CLI are as follows:

·        It has an online command to make setup React web app.

·        It allows an individual not to mug up all the configurations as they usually provide the way to set up and minimize the production-ready app.

·        Well, maintenance of the versions of the application.

 

Questions 12: How many types of Components can be created using React?

Generally, the React supports the two types of the component structure, which are as follows:

1)     Class-based components or Stateful.

2)    Function-based component or Stateless.

 

Questions 13: What do you mean by react-router-dom?

In general, the react-router-dom is usually considered the library that can be used to implement the web app-based routing functionality.

 

Questions 14: What is the key difference between ES5 and ES6 in syntax?

The key difference between the ES5 and ES6 in syntax generally lies in the component and import and export functions.

 

Questions 15:  What are the various features of React?

 Various important features inculcated with the React are as follows:

·         React generally follows the unidirectional data flow, or we can say that the data binding.

·        For the development of the view, the react usually follows the reusable or the composable UI (User Interface) components effectively.

·        React usually supports the server side.

·        React makes use of the virtual DOM instead of using the real DOM.

 

Questions 16:  What are error boundaries?

Error boundaries are generally used to provide a way for an individual to catch the particular amount of errors that are usually rendered in the render phase. And it is usually introduced in version 16 of React.

 

Questions 17: Name a few techniques to optimize React app performance?

In general, there are many ways through which one can easily optimize the performance of a React app, and they are as follows:

·        Using useMemo ().

·        Using React.PureComponent.

·        Lazy Loading.

·        Maintaining State Colocation.

 

Questions 18: What is the use of refs?

Refs are generally used to return any reference to a particular element, and this is the most asked interview question for the year 2022.

 

Questions 19: What are the major problems with the MVC framework?

Some of the major problems associated with the MVC framework are as follows:

·        Applications are generally slow and inefficient.

·        Lots of memory wastage is there.

·        Manipulation of the DOM was quite expensive.

 

Questions 20: What do you understand by the strict mode in React?

Generally, the strict mode is considered the tool to highlight potential application problems. Moreover, the strict mode does not provide any effective visible UI.