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 …
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What is Virtual DOM in ReactJS?
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 …
Read More »What is boilerplate in coding?
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 …
Read More »What is higher order function in JavaScript?
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 …
Read More »Interview questions and their answers regarding Node.js and Express.js:
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? …
Read More »Create a functional component & display the list. They provided the array like [“Ava”, “Anthony”, “Baddon”, “Baen”, “Caley”, “Caellum”]. I had to display those data as per image attached reactjs
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 …
Read More »For a given below object
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 …
Read More »Execute all the tasks in such a way that if there are no dependencies then the tasks can be started but if there are any dependencies then those tasks should execute once the dependency are completed. for the below tasks Object the output should be in the below way:-Input:-d-done b-done a-done c-done e-done
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 …
Read More »Uber NodeJS JavaScript and ReactJS interview questions answers
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: …
Read More »Top Angular interview questions and answers
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 …
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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 = …
Read More »What is the difference between useMemo and useCallback?
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 …
Read More »What is Node.js, and what are its main features?
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 …
Read More »Next.js is a framework built on top of React and Node.js, offering several advantages over using React and Node.js separately
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. …
Read More »What is javascript service workers?
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 …
Read More »What is IIFE in Javascript?
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 …
Read More »What is hoisting in javascript with example?
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, …
Read More »What are the differences between var, let and const in JavaScript?
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 …
Read More »What are truthy and falsy values in JavaScript?
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 …
Read More »How many ways have to initialise a JavaScript Array?
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 …
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