MINDTREE REACT JS INTERVIEW QUESTIONS

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

1. What are synthetic events in React?

SyntheticEvent is a cross-browser wrapper around browser’s native event. In React all of your event handlers will be passed instances of SyntheticEvent.

2. What do you understand by refs in React?

Refs are functions provided by React to access the DOM element and the React element that can be created on their own. They are used in cases where we want to change the value of a child component, without making use of props and all.

3. How do you modularize code in React?

React makes the modularization of code easy by introducing the component structure. With our components separated in their own files, all we have to do is figure out how to access the code defined in one file within a different file.

4. How are forms created in React?

Creating Forms in React:

class MyForm extends React.Component { render() { return ( <form> <h1>Hello</h1> <p>Enter your name:</p> <input type="text"/> </form> ); } ReactDOM.render(<MyForm />, document.getElementById(root));

5. What is Redux?

Redux is the open source knowable state container built for JavaScript apps and allows managing the application state. Applications that run consistently help run in different environments (client, server, and native) and are easy to test.

6. What are the advantages of Redux?

Redux makes debugging an app easy. Through logging behavior and status, coding errors, network errors and other types of bugs that may occur during development are easy to understand. Redux implementations can easily be evaluated as functions to alter the state of pure functions.

7. Why do we need a Router in React?

A router is much needed in React, used to manage multiple routes whenever a user types in a URL. If the route is present in the router for that corresponding URL, then the user is taken to the particular route.

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8. List down the advantages of React Router.

Benefits Of React Router

It is not necessary to set the browser history manually.
Link uses to navigate the internal links in the application. It is similar to the anchor tag.
It uses Switch feature for rendering.
The Router needs only a Single Child element.

9. What is the difference between Element and Component?

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

10. How to create components in React?

Thinking in React

Step 1: Break The UI Into A Component Hierarchy.
Step 2: Build A Static Version in React.
Step 3: Identify The Minimal (but complete) Representation Of UI State.
Step 4: Identify Where Your State Should Live.
Step 5: Add Inverse Data Flow

11. When to use a Class Component over a Function Component?

In class components, the render method will be called, whenever the state of the components changes. On the other hand, the Functional components render the UI based on the props. Class Components should be preferred whenever we have the requirement with the state of the component.

12. What is state in React?

The state is an instance of React Component Class can be defined as an object of a set of observable properties that control the behavior of the component. The heart of every React component is its “state”, an object that determines how that component renders & behaves.

13. What are props in React?

A prop is an object that stores the value of attributes of a tag and work similar to the HTML attributes. It gives a way to pass data from one component to other components. Props are passed to the component in the same way as arguments passed in a function.

14. What is the difference between state and props?

In a React component, props are variables passed to it by its parent component. State on the other hand is still variables, but directly initialized and managed by the component. The state can be initialized by props.

15. What are synthetic events in React?

A synthetic event is a cross-browser wrapper around the browser’s native event. It has the same interface as the browser’s native event, including stopPropagation() and preventDefault() , except the events work identically across all browsers.

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MINDTREE REACT JS INTERVIEW QUESTIONS