Xoriant Reactjs Developer Interview Questions and Answers

Closures and hoisting are important concepts in JavaScript.

• Closures refer to the ability of a function to access variables in its outer scope even after the function has returned.

• Hoisting is the behavior of moving variable and function declarations to the top of their respective scopes.

• Example of closures: function outer() { let x = 10; function inner() { console.log(x); } return inner; } const innerFunc = outer(); inn...read more

Hoisting is a JavaScript behavior where variable and function declarations are moved to the top of their containing scope.

• Hoisting applies to both variable and function declarations.

• Variable declarations are hoisted but not their initializations.

• Function declarations are fully hoisted, allowing them to be called before they are declared.

• Hoisting does not apply to variables declared with let or const.

• Hoisting can lead t...read more

Higher-order functions are functions that take one or more functions as arguments or return a function as their result.

• Higher-order functions can be used to create reusable code by abstracting common patterns.

• They enable functional programming paradigms like currying and composition.

• Examples of higher-order functions in JavaScript include map, filter, and reduce.

var is function scoped, let and const are block scoped.

• var can be redeclared and updated within its scope

• let can be updated but not redeclared within its scope

• const cannot be updated or redeclared once declared

• let and const are not hoisted like var

• const must be initialized during declaration

Hooks are a feature in React.js that allow developers to use state and other React features in functional components.

• Hooks are functions that let you use React features in functional components

• They allow you to use state and other React features without writing a class

• Hooks provide a way to reuse stateful logic between components

• Some commonly used hooks are useState, useEffect, and useContext

Var is function scoped, let is block scoped. Redux is a predictable state container, Flux is an architecture pattern.

• Var can be redeclared and updated within its scope, let cannot be redeclared but can be updated within its scope

• Redux has a single store for the entire application, while Flux has multiple stores

• Redux uses a unidirectional data flow, while Flux uses a bidirectional data flow

• Redux has middleware for handl...read more

Context API or Redux can be used as alternative ways for prop drilling in React.

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

• Implement Redux to manage global state and access data from any component without prop drilling.

• Consider using React's useContext hook with Context API for a simpler way to consume context in functional components.

Hosting is the process of storing a website or application on a server, while closure is a function that retains access to variables from its parent scope.

• Hosting involves storing a website or application on a server to make it accessible on the internet.

• Closure is a function that retains access to variables from its parent scope, even after the parent function has finished executing.

var, let, and const are used to declare variables in JavaScript. var has function scope, let has block scope, and const is a constant with block scope.

• var has function scope, meaning it is accessible throughout the function it is declared in.

• let has block scope, meaning it is only accessible within the block it is declared in.

• const is similar to let in terms of block scope, but the value cannot be reassigned.

Asynchronous programming allows tasks to run independently of the main program flow, improving performance and responsiveness.

• Asynchronous code does not block the main thread, allowing other tasks to continue while waiting for a response.

• Callbacks, promises, and async/await are common ways to handle asynchronous operations in JavaScript.

• Example: fetching data from an API while the rest of the application continues to r

The output for the given code snippets will be: 1) 20 2) ReferenceError: Cannot access 'b' before initialization 3) ReferenceError: b is not defined

• In the first snippet, variable 'a' is declared using 'var' after it is assigned a value, so it logs 20 without any issues.

• In the second snippet, variable 'b' is declared using 'let' after it is assigned a value, so it throws a ReferenceError as 'b' is accessed before initia...read more

Use HTML and CSS to center a div with text and apply animation

• Create a div element with text inside

• Apply CSS to center the div on the page using flexbox or margin auto

• Use CSS animations like keyframes to add animation effects

Semantic tags are HTML tags that provide meaning to the content they enclose, helping search engines and screen readers understand the structure of a webpage.

• Semantic tags help improve SEO by providing context to search engines.

• They also improve accessibility for screen readers by clearly defining the structure of a webpage.

• Examples of semantic tags include

  ,