British Car Auctions Front end Developer Interview Questions and Answers

Round duration - 60 Minutes
Round difficulty - Medium

This round consisted of some standard questions related to HTML , CSS , JS and basic Frontend develeoper practices .

Q1. What are the features of HTML5?
Ans. 
HTML5 is the latest version of the HTML standard with new features for web development.
• Support for multimedia elements like <video> and <audio>

• Canvas and SVG for graphics and animations

• Improved form controls and validation

• Offline storage capabilities with Local Storage and IndexedDB

• Geolocation API for location-based services
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Q2. Can you explain the CSS Box Model?
Ans. 
The CSS Box Model is a fundamental concept in CSS that defines the layout and spacing of elements on a webpage.
• The Box Model consists of content, padding, border, and margin.

• Content: The actual content of the box, such as text or images.

• Padding: Space between the content and the border.

• Border: The border surrounding the padding and content.

• Margin: Space outside the border, separating the element from other elements.

• Exa...read more
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Q3. What is prototype chaining in JavaScript?
Ans. 
Prototype chaining in JavaScript is the mechanism by which objects inherit properties and methods from other objects.
• In JavaScript, each object has a prototype property, which points to another object. When a property or method is accessed on an object, JavaScript will look for it in the object itself first, and then in its prototype chain.

• If the property or method is not found in the object, JavaScript will continue t...read more
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Q4. What are media elements in HTML?
Ans. 
Media elements in HTML are used to embed audio and video content on a webpage.
• Media elements include <audio> and <video> tags in HTML.

• They allow for the playback of audio and video files directly on a webpage.

• Attributes like src, controls, autoplay, and loop can be used to customize the behavior of media elements.

• Example: <video src='video.mp4' controls></video>
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Round duration - 70 Minutes
Round difficulty - Medium

This was a preety intense round revolving mainly around the core concepts of JavaScript and React . I was confident about my skills in JavaScript and React as I already had some projects in JS and React and I also completed the Guided Path of JS and React in CodeStudio which boosted my preparation and helped me crack these Frontend Interviews.

Q1. 
Swap Two Numbers Problem Statement
Given two integers a and b, your task is to swap these numbers and output the swapped values.
Input:
The first line contains a single integer 't', representing the num...read more
Ans. 
Swap two numbers 'a' and 'b' and output the swapped values.
• Create a temporary variable to store one of the numbers before swapping

• Assign the value of 'a' to 'b' and the temporary variable to 'a'

• Output the swapped values as 'b' followed by 'a'
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Q2. 
Sort Array Problem Statement
Given an array consisting of 'N' positive integers where each integer is either 0, 1, or 2, your task is to sort the given array in non-decreasing order.
Input:
Each input st...read more
Ans. 
Sort an array of 0s, 1s, and 2s in non-decreasing order.
• Use a counting sort algorithm to count the occurrences of 0s, 1s, and 2s in the array.

• Then reconstruct the array by placing the counted elements in order.

• Time complexity of the counting sort algorithm is O(N).
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Q3. Can you explain promises and their three states?
Ans. 
Promises are objects representing the eventual completion or failure of an asynchronous operation.
• Promises have three states: pending, fulfilled, and rejected.

• Pending: initial state, neither fulfilled nor rejected.

• Fulfilled: operation completed successfully.

• Rejected: operation failed.

• Promises can be chained using .then() to handle success and failure.

• Example: const promise = new Promise((resolve, reject) => { ... })...read more
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Q4. What are callbacks in JavaScript?
Ans. 
Callbacks in JavaScript are functions passed as arguments to other functions, to be executed later.
• Callbacks are commonly used in asynchronous operations, such as event handling or AJAX requests.

• They allow for more flexible and dynamic programming, by defining behavior that should happen after a certain event or task is completed.

• Example: setTimeout function in JavaScript takes a callback function as an argument to be ...read more
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Q5. What is the Same-origin policy?
Ans. 
Same-origin policy is a security measure in web browsers that restricts how a document or script loaded from one origin can interact with a resource from another origin.
• It prevents a web page from making requests to a different domain than the one it was loaded from.

• It helps protect user data and prevent malicious attacks like cross-site scripting (XSS).

• Cross-origin resource sharing (CORS) headers can be used to relax ...read more
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Q6. Can you explain the lifecycle of components in React?
Ans. 
Components in React go through various stages like mounting, updating, and unmounting.
• Components are created and inserted into the DOM during the mounting phase.

• During the updating phase, components can re-render due to changes in props or state.

• Components are removed from the DOM during the unmounting phase.

• Lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount are used to perform actio...read more
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Round duration - 30 Minutes
Round difficulty - Easy

This was a typical HR round with some standard Behavioral questions like my interests, weaknesses, strengths, family background, are you willing to relocate or travel , why Amdocs, CEO of Amdocs etc.

Q1. Why do you want to work at Amdocs?
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Q1. Based on html,css Javascript
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Q2. Based on ReactJs
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Q3. Javascript promise method
Ans. 
JavaScript Promise is an object representing the eventual completion or failure of an asynchronous operation.
• Promises are used to handle asynchronous operations such as fetching data from an API.

• They have three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() and .catch() methods.

• Promises can also be created using the Promise constructor.
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Q4. Javascript callback funtions
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Based on html, Css, Javascript and React-Js

Q1. How to handle state in functional components.
Ans. 
State in functional components can be managed using the useState hook in React.
• Use the useState hook to declare state variables in functional components.

• useState returns an array with the current state value and a function to update that value.

• Example: const [count, setCount] = useState(0);

• State variables should be immutable, so always use the setter function to update them.
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Q2. What is event loop in javascript.
Ans. 
Event loop in JavaScript is responsible for handling asynchronous operations by executing callback functions in a non-blocking way.
• Event loop is a mechanism that allows JavaScript to perform non-blocking operations.

• It continuously checks the call stack and the callback queue to see if there are any functions that need to be executed.

• If the call stack is empty, it takes the first function from the callback queue and pus...read more
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Q3. What is hosting in Javascript
Ans. 
Hosting in JavaScript refers to the process of declaring a variable or function before it is used in the code.
• Hosting allows you to use variables and functions before they are declared in the code.

• Variables are hoisted to the top of their scope, while functions are fully hoisted.

• Example: console.log(myVar); var myVar = 10; This will not throw an error because 'myVar' is hoisted to the top of the scope.
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Q1. What is mean by dom
Ans. 
DOM stands for Document Object Model, which is a programming interface for web documents.
• DOM is a representation of the structure of a web page, allowing scripts to dynamically access and update the content, structure, and style of the document.

• It provides a way for scripts to interact with the web page by accessing and manipulating elements like text, images, forms, etc.

• DOM is platform and language-independent, allowi...read more
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Q2. Explain promise in typescript
Ans. 
Promises in TypeScript are objects representing the eventual completion or failure of an asynchronous operation.
• Promises are used to handle asynchronous operations in a more readable and manageable way.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() to handle success and .catch() to handle errors.

• Example: const myPromise = new Promise((resolve, reject) => { ... ...read more
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Q3. Explain hooks in javascript
Ans. 
Hooks in JavaScript are functions that let you use state and other React features without writing a class.
• Hooks were introduced in React 16.8 to allow functional components to have state and lifecycle methods.

• useState() is a hook that allows you to add state to functional components.

• useEffect() is a hook that allows you to perform side effects in functional components.

• Custom hooks are functions that allow you to reuse ...read more
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Q4. Write a program 1 to 100 prime numbers
Ans. 
Generate an array of prime numbers from 1 to 100.
• Iterate from 1 to 100 and check if each number is prime

• A prime number is only divisible by 1 and itself

• Start with a list of prime numbers and check divisibility
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Verbal questions mostly asked and very easy

Opps and recursion and an array and string questions asked

Quite easy round it was very simple

Coding a frontend UI from provided image. And creating a fucntional star rating system

Q1. Designing a Component API in React using Typescript.
Ans. 
Designing a Component API in React using Typescript involves defining props, state, and methods for the component.
• Define the props interface to specify the expected input data for the component

• Use typescript types to ensure type safety and prevent runtime errors

• Define the state interface to manage the internal state of the component

• Implement methods to handle user interactions and component logic

• Document the component ...read more
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Q2. Create a function that can clear all the timer ids at once.
Ans. 
Function to clear all timer ids at once
• Create an array to store all timer ids

• Iterate through the array and clear each timer id using clearTimeout() function
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1hr

Q1. About the ReactJS, Javascrirp,HTML5,CSS3 Questions
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Q1. Salary Discussion only
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Q1. What is Event Loop ? How it works?
Ans. 
Event Loop is a mechanism in JavaScript that manages the execution of code and handles asynchronous operations.
• Event Loop continuously checks the call stack and the message queue.

• If the call stack is empty, it takes the first message from the queue and pushes it onto the call stack.

• If the message is a callback function, it is executed and removed from the call stack.

• If the message is not a callback function, it is pass...read more
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Q2. Make a set of 6 boxes Responsive in CSS
Ans. 
Use CSS to make a set of 6 boxes responsive
• Use percentage or viewport units for width and height

• Use media queries to adjust styles for different screen sizes

• Consider using flexbox or grid for layout

• Avoid using fixed pixel values

• Test on different devices and browsers

• Use CSS frameworks like Bootstrap or Foundation for easier implementation
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Q3. Hoisting & Closures Questions
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Q1. What's your Salary expectations ?
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