Call Us Now!
+91 9884412301 | +91 9600112302
info@credosystemz.com
Credo SystemzCredo Systemz
  • Courses
    • TRENDING TECHNOLOGIES TRAINING
    • RPA TRAINING
    • CLOUD COMPUTING TRAINING
    • BIG DATA TRAINING
    • WEB DEVELOPMENT TRAINING
    • MOBILE APPLICATION TRAINING
    • SOFTWARE TESTING TRAINING
    • MICROSOFT TECHNOLOGIES TRAINING
    • JAVA TRAINING
    • PROJECT MANAGEMENT TRAINING
    • DATA WAREHOUSING TRAINING
    • ORACLE TRAINING
    • DATABASE DEVELOPER TRAINING
    • OTHER TRAININGS
    • TRENDING TECHNOLOGIES
      Python Training Data Science Training Angular Training React JS Training ORACLE PRIMAVERA TRAINING Machine Learning Training Hadoop Training Amazon Web Services Training DevOps Training Azure Training PySpark Training MEAN Stack Training
    • RPA TRAINING
      Blue Prism Training UiPath Training Automation Anywhere
    • CLOUD COMPUTING
      Amazon Web Services Training AWS with Devops Training Azure Training AZ 104 Azure Administrator AZ 204 Azure Developer AZ 300 Azure Architect AZ 303 Azure Architect AZ 400 Azure Devops Google Cloud Platform Salesforce Training OpenNebula Training OpenStack Training OpenSpan Training
    • BIG DATA TRAINING
      Hadoop Training Big Data Analytics Training Spark Training
    • WEB DEVELOPMENT
      Angular Training Node JS Training React JS Training React Native Training Ionic Framework Training MEAN Stack Training PHP Training JavaScript Training CoffeeScript Training Less JS Training Graphics Design Training HTML Training CSS Training
    • MOBILE APPLICATION
      Android Training iOS Training iOS Swift Training Kotlin Training Flutter Dart Training
    • SOFTWARE TESTING
      Manual Testing Training UFT / QTP Training Selenium Training API Testing Training Selenium with Python Training Perfecto Mobile Testing Training ETL Testing Training JMeter Training LoadRunner Training Performance Engineering Big Data Testing Training Protractor Testing Training
    • MICROSOFT TECHNOLOGIES
      Dot Net Training MVC Framework ASP.NET MVC with Angular SharePoint Training Advanced Excel Training Excel Macro Training Azure Training Azure Infrastructure Solutions AZ 300 Azure Architect
    • JAVA TRAINING
      Core Java Training Java 8 Training Java J2EE Training Advanced Java Training Hibernate Training Spring Training Struts Training
    • PROJECT MANAGEMENT
      Oracle Primavera Training Primavera P6 Online Training Microsoft Project Training PMP Training ITIL Training Prince2 Training Scrum Master Training Business Analytics Training
    • DATA WAREHOUSING
      Tableau Training Power BI Training Qlikview Training Qlik Sense Training Informatica Training Microstrategy Training Teradata Training Cognos Training SAS Training
    • ORACLE TRAINING
      Oracle PL/SQL Training Oracle DBA Training Oracle Apps Technical Training Oracle Apps SCM Training Oracle Apps HRMS Training Oracle Apps Finance Training Oracle RAC Training PeopleSoft HCM Training PeopleSoft Finance Training
    • DATABASE DEVELOPER
      MongoDB Training Apache Cassandra Training Sybase Training Informix Training Performance Tuning Training
    • OTHER TRAININGS
      Ethical Hacking Training C C++ Training Unix Shell Scripting Training Tensorflow Training Data Modeling Training Workday Training PEGA Training Digital Marketing Training CCNA Training Arduino Training Elm Training Go Programming Training Rust Programming Training CYBER SECURITY TRAINING BIZTALK SERVER TRAINING Spoken English Course
  • Fresher Courses
    • ANGULAR TRAINING
    • REACT JS TRAINING
    • PYTHON TRAINING
    • JAVA TRAINING
    • SELENIUM TRAINING
    • FULLSTACK TRAINING
  • Placements
    • Career Guidance
      • Job Opportunities
      • Interview Questions
      • Resume Building
    • RECENT PLACEMENTS
  • About Us
    • Online Training
    • Corporate Training
    • Events
    • Reviews
      • Video Reviews
    • Become an instructor
  • Training
    • Trending Technologies Training
    • RPA TRAINING in Chennai
    • Cloud Computing Training
    • Big Data Hadoop Training in Chennai
    • Web Development Training
    • Mobile Application Training
    • Software Testing Training
    • Microsoft Technologies Training
    • Java Training
    • Project Management Training
    • Data Warehousing Training
    • Oracle Training
    • Database Developer Training
    • Other Training
  • Contact Us
  • Courses
    • TRENDING TECHNOLOGIES TRAINING
    • RPA TRAINING
    • CLOUD COMPUTING TRAINING
    • BIG DATA TRAINING
    • WEB DEVELOPMENT TRAINING
    • MOBILE APPLICATION TRAINING
    • SOFTWARE TESTING TRAINING
    • MICROSOFT TECHNOLOGIES TRAINING
    • JAVA TRAINING
    • PROJECT MANAGEMENT TRAINING
    • DATA WAREHOUSING TRAINING
    • ORACLE TRAINING
    • DATABASE DEVELOPER TRAINING
    • OTHER TRAININGS
    • TRENDING TECHNOLOGIES
      Python Training Data Science Training Angular Training React JS Training ORACLE PRIMAVERA TRAINING Machine Learning Training Hadoop Training Amazon Web Services Training DevOps Training Azure Training PySpark Training MEAN Stack Training
    • RPA TRAINING
      Blue Prism Training UiPath Training Automation Anywhere
    • CLOUD COMPUTING
      Amazon Web Services Training AWS with Devops Training Azure Training AZ 104 Azure Administrator AZ 204 Azure Developer AZ 300 Azure Architect AZ 303 Azure Architect AZ 400 Azure Devops Google Cloud Platform Salesforce Training OpenNebula Training OpenStack Training OpenSpan Training
    • BIG DATA TRAINING
      Hadoop Training Big Data Analytics Training Spark Training
    • WEB DEVELOPMENT
      Angular Training Node JS Training React JS Training React Native Training Ionic Framework Training MEAN Stack Training PHP Training JavaScript Training CoffeeScript Training Less JS Training Graphics Design Training HTML Training CSS Training
    • MOBILE APPLICATION
      Android Training iOS Training iOS Swift Training Kotlin Training Flutter Dart Training
    • SOFTWARE TESTING
      Manual Testing Training UFT / QTP Training Selenium Training API Testing Training Selenium with Python Training Perfecto Mobile Testing Training ETL Testing Training JMeter Training LoadRunner Training Performance Engineering Big Data Testing Training Protractor Testing Training
    • MICROSOFT TECHNOLOGIES
      Dot Net Training MVC Framework ASP.NET MVC with Angular SharePoint Training Advanced Excel Training Excel Macro Training Azure Training Azure Infrastructure Solutions AZ 300 Azure Architect
    • JAVA TRAINING
      Core Java Training Java 8 Training Java J2EE Training Advanced Java Training Hibernate Training Spring Training Struts Training
    • PROJECT MANAGEMENT
      Oracle Primavera Training Primavera P6 Online Training Microsoft Project Training PMP Training ITIL Training Prince2 Training Scrum Master Training Business Analytics Training
    • DATA WAREHOUSING
      Tableau Training Power BI Training Qlikview Training Qlik Sense Training Informatica Training Microstrategy Training Teradata Training Cognos Training SAS Training
    • ORACLE TRAINING
      Oracle PL/SQL Training Oracle DBA Training Oracle Apps Technical Training Oracle Apps SCM Training Oracle Apps HRMS Training Oracle Apps Finance Training Oracle RAC Training PeopleSoft HCM Training PeopleSoft Finance Training
    • DATABASE DEVELOPER
      MongoDB Training Apache Cassandra Training Sybase Training Informix Training Performance Tuning Training
    • OTHER TRAININGS
      Ethical Hacking Training C C++ Training Unix Shell Scripting Training Tensorflow Training Data Modeling Training Workday Training PEGA Training Digital Marketing Training CCNA Training Arduino Training Elm Training Go Programming Training Rust Programming Training CYBER SECURITY TRAINING BIZTALK SERVER TRAINING Spoken English Course
  • Fresher Courses
    • ANGULAR TRAINING
    • REACT JS TRAINING
    • PYTHON TRAINING
    • JAVA TRAINING
    • SELENIUM TRAINING
    • FULLSTACK TRAINING
  • Placements
    • Career Guidance
      • Job Opportunities
      • Interview Questions
      • Resume Building
    • RECENT PLACEMENTS
  • About Us
    • Online Training
    • Corporate Training
    • Events
    • Reviews
      • Video Reviews
    • Become an instructor
  • Training
    • Trending Technologies Training
    • RPA TRAINING in Chennai
    • Cloud Computing Training
    • Big Data Hadoop Training in Chennai
    • Web Development Training
    • Mobile Application Training
    • Software Testing Training
    • Microsoft Technologies Training
    • Java Training
    • Project Management Training
    • Data Warehousing Training
    • Oracle Training
    • Database Developer Training
    • Other Training
  • Contact Us

Contus React JS Interview Questions

  • Home
  • Contus React JS Interview Questions

Contus – React JS Interview Questions

Here is the list React JS Interview Questions which are recently asked in Contus company. These questions are included for both Freshers and Experienced professionals. Our React JS Training has Answered all the below Questions.


1. Give one basic difference between pros and state?

The difference is that state is something like attributes in OOP: it's something local to a class (component), used to better describe it. Props are like parameters - they are passed to a component from the caller of a component (the parent): as if you called a function with certain parameters.

2. What do you understand with the term polling?

Sometimes when building web applications, you're going to need to keep track of data being created or updated asynchronously by another service. Polling is one way to accomplish this, and all it is, is simply hitting an API's endpoint to retrieve any new data at a set interval of time.

3. When would you use a Class Component over a Functional Component?

If you are writing a presentational component which doesn't have its own state or needs to access a lifecycle hook, use functional component as much as possible. For state management you can use class component.

4. What do you mean by virtual DOM?

The virtual DOM (VDOM) is a programming concept where an ideal, or “virtual”, representation of a UI is kept in memory and synced with the “real” DOM by a library such as React DOM. They may also be considered a part of “virtual DOM” implementation in React.

5. Compare MVC with Flux?

Flux uses 'Stores' to cache any application associated with data or state whereas MVC model attempts to model a single object. MVC doesn't have the concept of the Store. The Store is more like a model in MVC, but it handles the state of several objects instead of just denoting a single database record.

6. What’s the difference between an Element and a Component in React?

React Element - It is a simple object that describes a DOM node and its attributes or properties you can say. It is an immutable description object and you can not apply any methods on it. React Component - It is a function or class that accepts an input and returns a React element.

7. Tell us three reasons behind the success of ReactJS?

  • React JS simplifies the overall process of scripting components.
  • It facilitates advanced maintenance and boosts productivity.
  • It guarantees quicker rendering.
Free PDF : Get our updated React JS Course Content pdf

8. What do you mean by prop?

Props” stands for properties. It is a special keyword in React which is used for passing data from one component to another. Logically, components are just like JavaScript functions. They accept random inputs and return React elements which tell what should be displayed on the screen.

9. What is meant by event handling?

Handling events with React elements is very similar to handling events on DOM elements. React events are named using camelCase, rather than lowercase. With JSX you pass a function as the event handler, rather than a string.

10. What are controlled and uncontrolled components?

In a controlled component, form data is handled by a React component. The alternative is uncontrolled components, where form data is handled by the DOM itself. To write an uncontrolled component, instead of writing an event handler for every state update, you can use a ref to get form values from the DOM.

11. Mention the key benefits of Flux?

  • Flux is open-source, easy to understand and maintain.
  • It is more of a design pattern than a formal framework.
  • It complements React as view and Runtime errors are reduced.
  • It follows the concept of Unidirectional Data Flow model.

12. What are pure functional Components?

A React component is considered pure if it renders the same output for the same state and props. Pure components have some performance improvements and render optimizations since React implements the shouldComponentUpdate() method for them with a shallow comparison for props and state

13. What happens during the lifecycle of a React component?

Every React Component has a lifecycle of its own; lifecycle of a component can be defined as the series of methods that are invoked in different stages of the component's existence.

Mounting: Mounting is the stage of rendering the JSX returned by the render method itself.

14. What do you know about React Router?

React Router, and dynamic, client-side routing, allows us to build a single-page web application with navigation without the page refreshing as the user navigates. React Router uses component structure to call components, which display the appropriate information

Book a Free Mock Interviews and Test your React JS skills with our Experts

TOP MNC REACT JS INTERVIEW QUESTIONS

Here we listed all React JS Interview Questions and Answers which are asked in Top MNCs. Periodically we update this page with recently asked Questions, please do visit our page often and be updated in React JS.

Accenture
Contus
Mindtree
Altimetrik Corp
Crux
TCS
Capgemini
Viasat
Crayon Data
Rectras
Infosys
Cognizant
Hexaware
Tenmiles
Verizon

To become a React JS Certified professional and join in your dream company, Enroll now for our Best React JS Training. We help you to crack any levels of React JS Interviews and We offering React JS Training with 100% Placements.

other top mnc React JS Interview Q&A

  • Accenture
  • TCS
  • Infosys
  • Contus
  • Capgemini
  • Cognizant
  • Mindtree
  • Viasat
  • Hexaware
  • Altrimetrik Corp
  • Crayon Data
  • Tenmiles
  • Crux
  • Rectras
  • Verizon

INDIA LOCATIONS

New #30,Old #16A,
Rajalakshmi Nagar, Velachery,
Chennai - 600 042.
Mobile: +91 9884412301

Plot No.8, Vinayaga Avenue,
Rajiv Gandhi Salai, Okkiampettai(OMR),
Chennai – 600 097.
Mobile: +91 9600112302

Refund/Cancellation Policy

INTERNATIONAL LOCATIONS

USA
Houchin Drive, Franklin, TN -37064
Tennessee
Email: info@credosystemz.com
Web: www.credosystemz.com
Chat With Us

UAE
Sima Electronic Building,
LLH Opposite,
Electra Street – Abu Dhabi
Email: info@credosystemz.com
Web: www.credosystemz.com
Chat With Us

Follow us on





TRENDING COURSES

  • Python Training in Chennai
  • Data Science Training in Chennai
  • Big Data Hadoop Training in Chennai
  • Machine Learning Training in Chennai
  • Selenium Training in Chennai
  • Angular Training in Chennai
  • Oracle Primavera P6 Online Training
  • Mean Stack Training in Chennai
  • DevOps Training in Chennai
  • Microsoft Azure Training in Chennai
  • GCP Training in Chennai

Copyright 2022 CREDO SYSTEMZ | All Rights Reserved.