Verizon – React JS Interview Questions

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

1. Clarify the Components lifecycle in ReactJS?

In React JS, every component creation process involves various lifecycle methods. These lifecycle methods are termed as component's lifecycle. These methods are not very complicated and called at various points during a component's life. The lifecycle of the component is divided into four phases. They are:

Initial Phase
Mounting Phase
Updating Phase
Unmounting Phase

2. What is Redux?

Redux is a predictable state container for JavaScript apps based on the Flux design pattern. Redux can be used together with React JS, or with any other view library. It is tiny (about 2kB) and has no dependencies.

3. What are the center standards of Redux?

Three Principles

Single source of truth. The global state of your application is stored in an object tree within a single store.
State is read-only. The only way to change the state is to emit an action, an object describing what happened.
Changes are made with pure functions.

4. What are the drawbacks of Redux contrasted with Flux?

Redux is not a pure Flux implementation but definitely inspired by Flux. Biggest difference is that it uses a single store that wraps a state object containing all the state for your application. Instead of creating stores like you'll do in Flux, you'll write reducer functions that will change a single object state.

5. Would I be able to dispatch an activity in reducer?

Dispatching an action within a reducer is an anti-pattern.

Your reducer should be without side effects, simply digesting the action payload and returning a new state object. Adding listeners and dispatching actions within the reducer can lead to chained actions and other side effects.

6. How to get to Redux store outside a part?

If you need to dispatch actions from outside a React component, the same technique will work: import the store, then call store. dispatch() , passing the action you need to dispatch. It works the same as the dispatch function you get from props via react-redux's connect function.

7. What are the drawbacks of MVW pattern

Communication between various MVVM components and data binding can be painful. Code reusability of views and view model is difficult. Managing view models and their state in nested views and complex UI's is difficult.

8. Are there any similitudes among Redux and RxJS?

RxJS can be used to do Reactive Programming and is a very thorough library with 250+ operators. And Redux is as described on the github repo "Redux is a predictable state container for JavaScript apps". Redux is just a tool to handle state in apps. But in comparison you could build a full app in just RxJS.

9. How to utilize interface() from React Redux?

Basic Redux and UI Integration

Create a Redux store.
Subscribe to updates.
Inside the subscription callback: Get the current store state. Extract the data needed by this piece of UI. Update the UI with the data.
If necessary, render the UI with initial state.
Respond to UI inputs by dispatching Redux actions.

10. What's the reason for at image in the Redux associate decorator?

The @ symbol is in fact a JavaScript expression currently proposed to signify decorators: Decorators make it possible to annotate and modify classes and properties at design time.

11. What is the contrast between React setting and React Redux?

Redux manages state and state transformations and is often used with React, but React has its own concept of state. ... Even if you choose to use Redux in your project, you will still need to make decisions on how much of your data is stored in Redux.

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12. How to make AJAX ask for in Redux?

you can apply redux-thunk middleware which allows you to define async actions. Here an example of reducer for async action. const booksReducer = (state = {}, action) => { switch (action. type) { case 'RESOLVED_GET_BOOK': return action.

13. Real Advantages of utilizing React.

React is an efficient, declarative, and flexible open-source JavaScript library for building simple, fast, and scalable frontends of web applications. Ever since its launch, it has taken the front-end development space by storm.

14. What is state in respond js ?

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. In other words, the State of a component is an object that holds some information that may change over the lifetime of the component.

15. What is props in respond js ?

Props are used to pass data from parent to child whereas the state is used for data manipulation inside the component. We can get the value of props from the parent component, where we get the value of state object from the initial data defined in the constructor() method.

16. What are ReactJS Components?

Components are independent and reusable bits of code. They serve the same purpose as JavaScript functions, but work in isolation and return HTML via a render() function. Components come in two types, Class components and Function components.

17. What’s the distinction b/w an Element and a Component in React?

React Element 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.

18. What are a three explanations for the accomplishment of ReactJS?

Permission to reuse React components significantly saves time.
One-direction data flow in ReactJS provides a stable code.
An open-source Facebook library: constantly developing and open to the community.

19. What is the difference between creating Element and clone Element?

CreateElement() functions to create React elements which are going to be used for the object representation of UI whereas cloneElement is used to clone an element and pass it new props.

20. What are the center standards of Redux?

Three Principles

Single source of truth. The global state of your application is stored in an object tree within a single store.
State is read-only. The only way to change the state is to emit an action, an object describing what happened.
Changes are made with pure functions.

21. Characterize State in React and the manner in which it is utilized in React.

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Verizon React JS Interview Questions