21 Essential React js Interview Questions and Answers

DOM is an abstraction of a structured code called HTML, also described as HTML DOM. For all the available DOM objects in ReactJS, there is a parallel virtual DOM object. It is nothing but can be considered as the lighter version of the true copy and is powerful in eliminating the complex code. It is also used as a Blue Print for performing several basic experiments.

Can be applied at any level of an application component hierarchy, which allows it to be adopted incrementally within a codebase. The simplest approach is to simply pass a selectedUserAddress prop from each component to the next in the hierarchy from the source component to the deeply nested component. Changes made to the VDOM are batched together to avoid unnecessary frequent changes to the DOM. If the second parameter contains an empty array, the callback will be executed only once as part of the first render cycle.

What is User Centered Design?

It is not likely possible to know everything beforehand when creating a project from scratch. Along the way, you’ll have to learn many different skills and get good at that. The setLocalStorage() function takes into account whether the passed value is a function or a simple variable value.

  • React interview questions commonly feature at Java developer interviews, mainly front-end interviews, as the framework helps perform a range of front-end programming tasks.
  • You should add more specific and relevant questions during the interview.
  • He specializes React Native, React , Laravel, Node.js, and GraphQL development as well as developing his skills with Go.
  • The combineReducers function takes an object whose keys correspond to the keys in the state, and whose values are the individual reducers that will manage those parts of the state.
  • ReactJS is a very popular library, especially among companies that want to create their own mobile applications.

In the context of React development, this means avoiding the temptation to build out features or components that are not immediately necessary. Instead, developers should focus on building out the minimum viable product and adding new features as needed. This helps to avoid unnecessary complexity and maintainability issues in the codebase. Both redux-thunk and redux-saga are middleware libraries for Redux, a popular state management library for JavaScript applications.

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We can use procedural, object-oriented, and functional programming paradigms simultaneously in JavaScript, which makes it more powerful. The candidate should be able to explain the differences between the two. A good React developer should be able to define states and props using common terms that a non-technical person can also understand. Yes, resumes offer a wealth of information about a job candidate’s skills and experience.

front end developer react js interview questions

It is important to note that accessibility is a continuous process and should be considered throughout the development of your React application. The use of tools, such as linting rules and accessibility testing tools, can also help ensure that your application is accessible. A component that needs to access the context data can consume it by using the useContext hook or the Consumer component. To make the context available to a component, a parent component needs to provide it using the Provider component.

State some basic design element

So all the component’s state are stored in the Store and they receive updates from the Store itself. The single state tree makes it easier to keep track of changes over time and debug or inspect the application. Flux is an architectural pattern which enforces the uni-directional data flow. It controls derived data and enables communication between multiple components using a central Store which has authority for all data. Any update in data throughout the application must occur here only. Flux provides stability to the application and reduces run-time errors.

The change in state can happen as a response to user action or system-generated events. It determines the behavior of the component and how it will render. Here’s a comprehensive list of all the common ReactJS interview questions from basic to advanced levels that are frequently asked in interviews. A Full stack Javascript Developer (React.js + Node.js) is a great fit for any organization that is looking to build or improve upon a web application.

Best React Interview Questions And Answers

So far, if you have any doubts about the above React interview questions and answers, please ask your questions in the section below. In case you have any doubts about these Basic React interview questions and answers, please leave your questions in the comment section below. Aspect is more than just an interview intelligence platform—it’s a game-changer for your entire organization. For our part, we provide full technical support and even make improvements if necessary. This library is easy to understand and master, therefore, it allows teams to work faster.

front end developer react js interview questions

A Higher Order Component in React is a function that takes a component as an argument and returns a new component with additional props. The purpose of a HOC is to reuse logic across multiple components. An HOC is not a “part” of React, it’s a pattern in React for reusing component logic. In React, a static component is a component that is defined with a fixed set of properties or attributes and does not change during its lifecycle. A static component is defined using a simple JavaScript function that returns a tree of elements that represent the component’s UI.

React Components – React Interview Questions

Submitted questions and answers are subject to review and editing, and may or may not be selected for posting, at the sole discretion of Toptal, LLC. Mixins are possible, but not built-in to React’s ES6 API. However, the ES6 API makes it easier to create a custom Component that extends another custom Component. Many React utility libraries on npm provide a single function to bind all handlers in the constructor, just like React does.

front end developer react js interview questions

It maintains consistent structure and behavior and is used to develop single-page web applications. If you need to render more than one element, all of the elements must be inside one parent tag like , . It is required for each component to have a render() function. This function returns the HTML, which is to be displayed in the component.