Wipro Reactjs Developer Interview Questions, Process, and Tips

Closure is a feature in JavaScript that allows a function to access variables in its outer scope.

• A closure is created when a function is defined inside another function.

• The inner function has access to the outer function's variables and parameters.

• The outer function's variables and parameters are not accessible from outside the closure.

• Closures can be used to create private variables and methods.

• Example: function outer...read more

ES6 features are new additions to JavaScript language syntax and functionality.

• Arrow functions

• Template literals

• Let and const keywords

• Destructuring assignment

• Spread and rest operators

• Classes

• Modules

• Promises

• Default parameters

• Object.assign()

• Symbol data type

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