Sandvok Softwares Front end Developer Interview Questions and Answers for Experienced

Q1. Explain about react js?
Ans. 
React JS is a JavaScript library for building user interfaces.
• React is component-based, allowing for reusable UI elements.

• Uses a virtual DOM for efficient updates to the actual DOM.

• Supports server-side rendering for improved performance.

• Uses JSX syntax to write HTML within JavaScript code.

• State management is handled using props and state.
Answered by AI
Add your answer
Q2. Explain about angular?
Ans. 
Angular is a popular front-end framework developed by Google for building dynamic web applications.
• Angular is based on TypeScript, a superset of JavaScript.

• It uses a component-based architecture for building reusable UI components.

• Angular provides features like data binding, dependency injection, and routing.

• It has a powerful CLI for scaffolding and managing projects.

• Angular has a large ecosystem of libraries and tools
Answered by AI
Add your answer

Q1. Let var const in JavaScript
Ans. 
var and const are used to declare variables in JavaScript, with var being mutable and const being immutable.
• var is used to declare variables that can be reassigned and updated

• const is used to declare variables that cannot be reassigned or updated

• let is another keyword used for declaring variables, similar to var but with block scope
Answered by AI
Add your answer
Q2. Error boundary and how to handle
Ans. 
Error boundary is a React component that catches JavaScript errors anywhere in a component tree and logs those errors.
• Error boundaries are React components that catch JavaScript errors in their child component tree.

• They are used to prevent the entire UI from crashing due to a single error.

• Error boundaries work like a JavaScript catch {} block, but for components.

• They are defined using componentDidCatch lifecycle method
Answered by AI
Add your answer
Q3. Event.bind and event.property
Add your answer
Q4. Use of never in typescript
Ans. 
The 'never' type in TypeScript represents a value that will never occur.
• Used to indicate that a function will not return a value

• Commonly used in union types to exclude certain values

• Helps catch potential errors at compile time
Answered by AI
Add your answer
Q5. What hooks you have used
Ans. 
I have used React hooks such as useState, useEffect, useContext, and useRef in my projects.
• useState

• useEffect

• useContext

• useRef
Answered by AI
Add your answer
Q6. What is difference between use reducer and use state
Ans. 
useReducer is preferred for managing complex state logic, while useState is simpler for basic state management.
• useReducer is more suitable for managing complex state logic and multiple state values

• useState is simpler and more straightforward for basic state management with a single value

• useReducer allows for more organized and centralized state updates through actions and reducers

• useState is commonly used for simple co
Answered by AI
Add your answer
Q7. Why we use state and props
Add your answer
Q8. How you will pass data from parent to child
Ans. 
Data can be passed from parent to child components in React using props.
• Pass data as props from parent component to child component

• Use state management libraries like Redux or Context API for complex data sharing

• Use callback functions to pass data from child to parent components
Answered by AI
Add your answer
Q9. Write your own custom hook
Ans. 
Custom hook to fetch data from an API
• Create a function that uses the useState and useEffect hooks

• Use the fetch API to make a request to the desired endpoint

• Return the fetched data and loading state in an array
Answered by AI
Add your answer
Q10. Explain map filter and reduce functions
Ans. 
Map, filter, and reduce are higher-order functions in JavaScript used to manipulate arrays.
• Map: Transforms each element in an array and returns a new array with the transformed elements.

• Example: [1, 2, 3].map(num => num * 2) returns [2, 4, 6].

• Filter: Returns a new array with elements that pass a certain condition.

• Example: [1, 2, 3].filter(num => num > 1) returns [2, 3].

• Reduce: Applies a function against an accumulator ...read more
Answered by AI
Add your answer
Q11. How you can clone an object
Ans. 
To clone an object in JavaScript, you can use the spread operator or Object.assign() method.
• Use the spread operator to create a shallow copy of an object: const clonedObj = { ...originalObj };

• Use Object.assign() method to create a shallow copy of an object: const clonedObj = Object.assign({}, originalObj);

• For deep cloning, you can use libraries like Lodash or write a custom function to recursively clone nested objects.
Answered by AI
Add your answer
Q12. What are the three stages of event propagation and how to handle it
Ans. 
Event propagation consists of three stages: capturing, target, and bubbling.
• Capturing phase: Events are captured from the outermost element to the target element.

• Target phase: Event reaches the target element where the event originated.

• Bubbling phase: Events bubble up from the target element to the outermost element.
Answered by AI
Add your answer
Q13. How to handle errors in your react application
Ans. 
Errors in a React application can be handled by using error boundaries, try-catch blocks, and displaying error messages to users.
• Use error boundaries to catch errors in components and display a fallback UI

• Wrap code that may throw errors in try-catch blocks to handle exceptions

• Use libraries like React Error Boundary to easily implement error handling

• Display error messages to users to inform them about the issue and poss
Answered by AI
Add your answer
Q14. Write code to call fake api and display the title where category is “some category “
Add your answer

Q1. Javascipt question
Add your answer
Q2. Promises, filter, map, What is single page , mulitple page application, opened google page by search for one product in that using console filter it only for sony products only
Add your answer
Q3. What is DOM, what is the use of that
Ans. 
DOM stands for Document Object Model, it is a programming interface for web documents. It represents the structure of a document as a tree of objects.
• DOM is used to interact with HTML and XML documents in a structured way

• It allows developers to manipulate the content, structure, and style of a website dynamically

• DOM provides methods and properties to access and modify elements on a web page

• Example: document.getElementB...read more
Answered by AI
Add your answer
Q4. What is the output if u type document in console
Ans. 
The output will display the document object in the console.
• Typing 'document' in the console will return the document object, which represents the current HTML document.

• The document object provides access to the content and structure of the webpage, allowing manipulation of elements and properties.
Answered by AI
Add your answer

Q1. How to handle form validation?
Ans. 
Form validation can be handled using client-side and server-side validation techniques.
• Use HTML5 form validation attributes like required, pattern, min, max, etc.

• Implement client-side validation using JavaScript to provide instant feedback to users.

• Perform server-side validation to ensure data integrity and security.

• Display error messages next to the input fields for better user experience.

• Use a combination of front-en...read more
Answered by AI
Add your answer
Q2. Explain the concept of redux-toolkit
Ans. 
Redux Toolkit is an official, opinionated, batteries-included toolset for efficient Redux development.
• Redux Toolkit simplifies Redux code by providing a set of tools and best practices

• It includes utilities like createSlice, createReducer, configureStore, and createAsyncThunk

• Helps in writing concise and readable Redux code with less boilerplate

• Encourages the use of Immer for writing immutable updates in a more intuitive
Answered by AI
Add your answer

Q1. What is AOT And JIT How angular different from react Route guard
Ans. 
AOT (Ahead-of-Time) and JIT (Just-in-Time) are compilation techniques used in Angular. Angular and React differ in their architecture and data binding approach. Route guards in Angular are used to control access to routes.
• AOT compilation in Angular converts TypeScript code into efficient JavaScript code during the build process, resulting in faster rendering and smaller bundle sizes.

• JIT compilation in Angular compiles ...read more
Answered by AI
Add your answer
Q2. How angular application build
Ans. 
Angular applications are built using the Angular CLI, which provides a command-line interface for creating, building, and serving Angular projects.
• Angular applications are built using the Angular CLI (Command Line Interface)

• The Angular CLI provides commands for creating new projects, generating components, services, modules, etc.

• To build an Angular application, you can use the 'ng build' command which compiles the appl
Answered by AI
Add your answer
Q3. Project discussion
Add your answer

Q1. Angular lifecycle hooks
Add your answer
Q2. JS interview questions
Add your answer

Recurrsion tree implementation with angular

Given time aptitude must be cleared

2 codings for 1 hour

Q1. 1. Difference between client-side and server side scripting? 2. What is destructuring? 3. What is HOC? 4. Write code to combine nested array 5. Write code to count the number of vowels in a string
Ans. 
1. Client-side scripting runs on the user's browser, while server-side scripting runs on the server. 2. Destructuring is a way to extract values from objects and arrays. 3. HOC stands for Higher Order Component in React. 4. Combining nested arrays involves flattening them into a single array. 5. Counting vowels in a string involves iterating through the characters and checking if they are vowels.
• Client-side scripting e...read more
Answered by AI
Add your answer