Engineer Sushil Kumar Sushil Kumar Profile

1. What is the purpose of app.use() in Express.js? Answer: In Express.js, app.use() is a method used to add middleware to your application. Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle. They …

In React, the Virtual DOM (Document Object Model) is a lightweight copy of the actual DOM. The DOM represents the structure of the document rendered by a browser, and manipulating it directly can be inefficient and slow, especially when dealing with complex UI updates. Here’s how the Virtual DOM works …

A “boilerplate” in code refers to sections of code that are repeated in multiple places with little to no variation. Boilerplate code is often used to set up the basic structure of an application, include necessary libraries, or provide a consistent foundation for more complex functionality. Here are a few …

A higher-order function is a function that either takes another function as an argument or returns a function as a result, or both. In JavaScript, functions are first-class citizens, meaning they can be treated like any other value, such as numbers or strings. This enables higher-order functions to be a …

Node.js What is Node.js? Node.js is a JavaScript runtime built on Chrome’s V8 JavaScript engine, designed to build scalable network applications. How does Node.js work? Node.js operates on a single-threaded event loop architecture that uses non-blocking I/O operations to handle multiple connections concurrently. What are the key features of Node.js? …

To display a list of names in a React functional component based on a provided array, you can follow a structured approach to render the data dynamically. I’ll walk you through the entire process of creating a functional component that will display the names as per the design specification. Let’s …

const exampleObj = {     taxi:       “a car licensed to transport passengers in return for payment of a fare”,     food: {       sushi:         “a traditional Japanese dish of prepared rice accompanied by seafood and vegetables”,       apple: {         Honeycrisp:           “an apple cultivar developed at the …

NodejsJavaScript const tasks = { 'd': ['b', 'c'], 'b': ['a'], 'a': [], 'c': [], 'e': ['d'] }; // Helper function to perform topological sort function topologicalSort(tasks) { const inDegree = {}; const adjList = {}; const zeroInDegreeQueue = []; const sortedOrder = []; // Initialize inDegree and adjList for (const …

Deep Copy vs Shallow Copy Shallow Copy A shallow copy creates a new object with a new reference, but the properties of the new object refer to the same memory locations as the properties of the original object. JavaScript Code Example: const original = { a: 1, b: { c: …

1. What is Angular? Answer: Angular is a platform and framework for building single-page client applications using HTML and TypeScript. It is developed and maintained by Google. 2. What is TypeScript? Answer: TypeScript is a superset of JavaScript that adds static typing to the language. Angular applications are written in …

You write a function to find max number from array using es6? 2 / 2ChatGPT ChatGPT Sure, you can use the spread operator (…) along with the Math.max() function to find the maximum number in an array in ES6. Here’s a function that does that: javascriptCopy code const findMaxNumber = …

useMemo and useCallback are both hooks provided by React that aim to optimize performance by memoizing values or functions, respectively. However, they serve different purposes: useMemo: useMemo is used to memoize the result of a computation. It’s particularly useful when you have a computation that is expensive and you want …

Sample Answer: Node.js is an open-source, server-side JavaScript runtime built on Chrome’s V8 JavaScript engine. It allows developers to build scalable, high-performance network applications using JavaScript, a language traditionally associated with client-side scripting in web browsers. Main Features of Node.js: Non-blocking I/O Model: Node.js is built on an event-driven, non-blocking …

Simplified Setup: React.js requires manual configuration for features like server-side rendering (SSR), routing, and code splitting. Setting up a React project typically involves configuring tools like webpack and babel, which can be complex and time-consuming. Next.js abstracts away much of this configuration, providing a pre-configured setup out of the box. …

Service workers are a crucial component of modern web development, particularly in the realm of Progressive Web Apps (PWAs). Essentially, service workers are scripts that run in the background of a web application, separate from the web page, intercepting and handling network requests and enabling features like offline support, push …

IIFE stands for Immediately Invoked Function Expression. It’s a common pattern in JavaScript where you define and execute a function all in one go. Here’s a basic example: (function() { // Your code here })(); This construct creates a function expression enclosed within parentheses (function(){}), and then immediately invokes it …

Hoisting in JavaScript is a behavior where variable and function declarations are moved to the top of their containing scope during the compilation phase, regardless of where they are declared in the code. This means that you can access variables and functions before they are declared in your code. However, …

var, let, and const are all used for variable declaration in JavaScript, but they have some differences in terms of scope, hoisting, and mutability: var: Variables declared with var are function-scoped or globally scoped, but not block-scoped. They are hoisted to the top of their function or global scope, which …

In JavaScript, a value is considered “truthy” if it evaluates to true when evaluated in a boolean context. Conversely, a value is considered “falsy” if it evaluates to false when evaluated in a boolean context. Here’s a breakdown of truthy and falsy values in JavaScript: Truthy values: Non-empty strings: Any …

Sure, there are several ways to initialize a JavaScript array. Here are some common methods: 1. **Using an array literal**: The simplest way to create an array is by using square brackets `[]`: const arr1 = []; // Empty array const arr2 = [1, 2, 3]; // Array with elements …