10+ Infosys Front end Developer Interview Questions and Answers

jQuery is a fast, small, and feature-rich JavaScript library.

• jQuery simplifies HTML document traversing, event handling, and animating.

• It provides a set of methods for AJAX interactions and DOM manipulation.

• jQuery is cross-platform and supports a wide range of browsers.

• It has a large community and a vast number of plugins available.

• Project architecture depends on the specific project and its requirements.

Controlled components are React components whose value is controlled by React, while uncontrolled components are not.

• Controlled components are typically used for forms and inputs

• Uncontrolled components are typically used for simple inputs like text fields

• Controlled components use the 'value' prop to set the value of the component

• Uncontrolled components use the 'defaultValue' prop to set the initial value of the component

• Controlled components allow for more control and validat...read more

A computer is an electronic device that can perform various tasks by executing instructions given to it.

• A computer is made up of hardware components such as CPU, memory, and storage devices.

• It runs on an operating system and software applications.

• Computers can be used for various purposes such as communication, entertainment, and work.

• Examples of computers include desktops, laptops, tablets, and smartphones.

HTML is the standard markup language for creating web pages and applications.

• HTML stands for HyperText Markup Language

• It is used to structure content on the web

• HTML elements are used to define the different parts of a webpage

• Examples include <h1> for headings, <p> for paragraphs, and <img> for images

Semantic HTML focuses on the meaning and structure of content, while display properties in CSS control how elements are visually displayed on a webpage.

• Semantic HTML uses tags that convey the meaning of the content, such as <header>, <nav>, <article>, <section>, <footer>.

• Display properties in CSS include properties like display: block, display: inline, display: inline-block, display: flex, display: grid.

• Using semantic HTML helps improve accessibility, SEO, and overall code ma...read more

Redux is a predictable state container for JavaScript apps.

• Redux is a library for managing application state

• It provides a centralized store for all the state of an application

• It uses a single source of truth principle

• It allows for predictable state changes through actions and reducers

• It is commonly used with React for building complex UIs

Hoisting is a mechanism in JS where variables and functions are moved to the top of their scope. Array methods are built-in functions to manipulate arrays.

• Hoisting applies to variable and function declarations

• Variables declared with let and const are not hoisted

• Array methods include push(), pop(), shift(), unshift(), splice(), slice(), forEach(), map(), filter(), reduce()

• push() adds an element to the end of an array

• pop() removes the last element of an array

• shift() removes the...read more

Promise is an object representing the eventual completion or failure of an asynchronous operation.

• Promises are used to handle asynchronous operations in JavaScript

• They are a cleaner alternative to callbacks

• Promises have three states: pending, fulfilled, or rejected

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

• Example: new Promise((resolve, reject) => {...})

HTML main features include structure, content, and semantics. Semantics refers to the meaning and purpose of the content.

• HTML provides structure to web pages through elements like <header>, <footer>, <nav>, etc.

• Content is added to HTML pages using tags like <p>, <img>, <ul>, etc.

• Semantics in HTML refers to using elements that convey meaning, such as <article>, <section>, <aside>, etc.

• Semantic HTML helps improve accessibility, SEO, and overall understanding of the content.

Form validation in React ensures user input is correct before submission.

• Use controlled components to manage form state

• Create validation functions to check input

• Display error messages for invalid input

• Disable submit button until form is valid

• Consider using a library like Formik or Yup for easier validation

React hooks are functions that allow functional components to use state and lifecycle methods.

• Hooks were introduced in React 16.8

• useState() is a hook that allows state to be used in functional components

• useEffect() is a hook that allows lifecycle methods to be used in functional components

• Custom hooks can be created to reuse stateful logic across components