Prodapt Reactjs Developer Interview Questions and Answers

Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope.

• Variables declared with var are hoisted to the top of their scope

• Function declarations are hoisted before variables

• Function expressions are not hoisted

• Let and const declarations are not hoisted

Promises are a way to handle asynchronous operations in JavaScript.

• Promises represent a value that may not be available yet.

• They have three states: pending, fulfilled, and rejected.

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

• They help avoid callback hell and make code more readable.

• Example: new Promise((resolve, reject) => { ... }).then(result => { ... }).catch(error => { ... })

ES6 features are modern JavaScript syntax and features that make code more concise and readable.

• Arrow functions for concise function syntax

• Template literals for easier string interpolation

• Let and const for block-scoped variables

• Destructuring for easily extracting values from objects and arrays

• Spread and rest operators for easily manipulating arrays and objects

• Classes for object-oriented programming

• Modules for better co

Given an array of integers, return the sum of all even numbers.

• Use Array.reduce() method to iterate over the array and sum the even numbers.

• Use the modulo operator (%) to check if a number is even.