20+ TCS Front end Developer Interview Questions and Answers

Allocate books to students in a way that minimizes the maximum number of pages assigned to a student.

• Iterate through possible allocations and calculate the maximum pages assigned to a student.

• Find the minimum of these maximums to get the optimal allocation.

• Return the minimum pages allocated in each test case, or -1 if not possible.

React middlewares are functions that intercept and modify requests and responses in a React application.

• Middlewares are used to add additional functionality to an application without modifying the core code.

• They can be used for authentication, logging, error handling, and more.

• Examples of React middlewares include Redux Thunk, Redux Saga, and React Router.

• They are typically implemented using higher-order functions.

• Middlewares can be chained together to create a pipeline of fu...read more

Redux is a predictable state container for JavaScript apps. It helps manage the state of an application in a centralized way.

• Redux is a state management library commonly used with React to manage the state of an application.

• It follows a unidirectional data flow pattern, where the state is stored in a single store and changes are made through actions and reducers.

• Redux allows for a more structured way of managing state compared to local component state in React.

• Context, on the...read more

JavaScript closures, TDZ, hoisting, and the JavaScript engine are key concepts in understanding how JavaScript works.

• JavaScript closures are functions that have access to variables from their outer scope even after the outer function has finished executing.

• Temporal Dead Zone (TDZ) is the period between entering a scope and the variable being declared where accessing the variable results in a ReferenceError.

• Hoisting is the JavaScript behavior where variable and function declar...read more

visibility: hidden hides an element but still takes up space, while display: none hides an element and removes it from the flow of the document.

• visibility: hidden hides the element but it still occupies space on the page

• display: none hides the element and removes it from the document flow

• visibility: hidden elements are still rendered, just not visible

• display: none elements are not rendered at all

Box model is a concept in CSS where every HTML element is considered as a rectangular box with content, padding, border, and margin.

• Content is the actual content of the element

• Padding is the space between the content and the border

• Border is the line that surrounds the padding and content

• Margin is the space between the border and the adjacent elements

• Box-sizing property can be used to change the default box model behavior

Yes, React Native Context API is a way to manage global state in React Native applications.

• Context API allows passing data through the component tree without having to pass props down manually at every level.

• It is useful for managing global state such as user authentication, theme, and language preferences.

• Context API consists of two parts: the Provider component and the Consumer component.

• The Provider component is used to wrap the components that need access to the global st...read more

No, Java does not support multiple inheritance.

• Java only supports single inheritance through classes.

• However, multiple inheritance can be achieved through interfaces.

• Diamond problem can be avoided in interfaces by implementing default methods.

• Example: class A extends B implements C, D {}

React Native functional components have limited lifecycle methods compared to class components.

• Functional components use useEffect() instead of componentDidMount() and componentDidUpdate()

• useEffect() can be used to handle component mount, update, and unmount

• useEffect() takes a callback function and an array of dependencies as arguments

• The callback function can return a cleanup function to handle component unmount

• Functional components do not have access to shouldComponentUpdat...read more

API stands for Application Programming Interface. It is a set of rules and protocols that allows different software applications to communicate with each other.

• APIs define the methods and data formats that applications can use to request and exchange information.

• They allow developers to access the functionality of a system or service without needing to understand its internal workings.

• Examples of APIs include Google Maps API for embedding maps in websites, Twitter API for acc...read more

SQL Server stored procedures and functions

• Stored procedures are precompiled SQL statements that can be executed with parameters

• Functions return a single value and can be used in SQL statements

• Both can improve performance and security by reducing network traffic and preventing SQL injection attacks

Spread operator allows an iterable to be expanded in places where zero or more arguments are expected. Rest operator collects all the remaining elements into an array.

• Spread operator is denoted by three dots (...)

• Spread operator can be used to copy an array or object

• Rest operator is also denoted by three dots (...) and is used in function parameters to collect all remaining arguments into an array

Front end development is the creation of the user interface and user experience of a website or application.

• Involves HTML, CSS, and JavaScript

• Focuses on the visual and interactive aspects of a website or application

• Requires knowledge of design principles and user behavior

• Examples include creating responsive layouts, implementing animations, and optimizing performance

CSS stands for Cascading Style Sheets and HTML stands for HyperText Markup Language.

• CSS - Cascading Style Sheets is used for styling web pages

• HTML - HyperText Markup Language is used for creating the structure of web pages

Props in React are read-only properties that are passed from a parent component to a child component.

• Props allow data to be passed down the component tree.

• Props are immutable and cannot be changed by the child component.

• Props are accessed in the child component using this.props.

Angular releases new versions regularly with updates and improvements.

• Angular follows a semantic versioning scheme with major, minor, and patch updates.

• Major updates introduce breaking changes and new features.

• Minor updates add new features and improvements.

• Patch updates include bug fixes and minor enhancements.

• For example, Angular 10 introduced stricter types, improved performance, and updated dependencies.

State and props are two important concepts in React for managing and passing data between components.

• State is used to store and manage data within a component. It is mutable and can be updated using setState() method.

• Props (short for properties) are used to pass data from parent to child components. They are immutable.

• State is internal to a component, while props are external and passed down from parent components.

• Example: State can be used to store form input values, while p...read more

Props are used to pass data from parent to child components, while state is used to manage data within a component.

• Props are read-only and cannot be modified by the component receiving them.

• State is mutable and can be changed by the component that owns it.

• Props are passed down from parent components, while state is managed locally within a component.

• Example: Passing a user's name as a prop to a child component vs. storing the user's input in a form field as state.

Pure functions are functions that always return the same output for the same input and have no side effects.

• Always return the same output for the same input

• Have no side effects, meaning they do not modify external state or variables

• Pure functions are predictable and easier to test and debug

Loops are used to repeatedly execute a block of code until a certain condition is met.

• Use 'for' loop to iterate over a block of code a specified number of times

• Use 'while' loop to execute a block of code as long as a specified condition is true

• Use 'do...while' loop to execute a block of code once, and then repeat the loop as long as a specified condition is true

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.