NxtWave Intern Interview Questions and Answers for Freshers

let is mutable and can be reassigned, const is immutable and cannot be reassigned

• let allows reassignment of values, const does not

• const must be initialized with a value, let can be declared without a value

• const is block-scoped, let is function-scoped

Closures are functions that have access to variables from their containing scope even after the parent function has finished executing.

• Closures allow functions to maintain access to variables from their parent scope

• They are created when a function is defined within another function

• Closures are commonly used in event handlers and callbacks

typeof null returns 'object' in JavaScript.

• typeof null is 'object' in JavaScript

• This is a historical bug in JavaScript that has not been fixed for backward compatibility

• Example: console.log(typeof null) will output 'object'

Finding palindrome strings in an array of strings.

• Iterate through each string in the array.

• For each string, check if it is equal to its reverse to determine if it is a palindrome.

• Store palindrome strings in a separate array or print them out.

Debouncing is a technique used to limit the rate at which a function is called.

• Debouncing is used to prevent multiple rapid calls to a function, typically in response to user input.

• It involves setting a delay before allowing the function to be called again.

• Example: Debouncing a search input field to only trigger the search function after the user has stopped typing for a certain period.

React is a JavaScript library for building user interfaces. It is different from Angular in various ways.

• React is a library while Angular is a framework

• React uses virtual DOM while Angular uses real DOM

• React is more flexible and easier to learn than Angular

• Deep copy creates a new object with the same values while shallow copy creates a new reference to the same object

• Hoisting is a JavaScript mechanism where variables a...read more

Implement custom hooks and array flat method

• Custom hooks are reusable functions that allow you to extract component logic into reusable functions

• Array flat method is used to flatten an array of nested arrays into a single array

• To implement custom hooks, create a function that uses the useState and useEffect hooks

• To implement array flat method, use the reduce method to flatten the array

var, let, and const are all used to declare variables in JavaScript, but they have different scoping rules and behaviors.

• var has function scope and can be redeclared and reassigned

• let has block scope and can be reassigned but not redeclared

• const has block scope and cannot be reassigned or redeclared

• Use const for values that won't change, let for values that will, and avoid var

CSS box model defines the layout of elements on a webpage. Padding and margin can apply to block-level elements but not to inline elements.

• CSS box model consists of content, padding, border, and margin around an element.

• Padding adds space inside the border of an element.

• Margin adds space outside the border of an element.

• Padding and margin can apply to block-level elements like <div> but not to inline elements lik

Arrow functions are shorter syntax for writing function expressions.

• Arrow functions do not have their own 'this' keyword.

• Arrow functions cannot be used as constructors.

• Arrow functions do not have the 'arguments' object.

• Arrow functions are more concise and easier to read.

• Regular functions are better for methods and constructors.

JavaScript asynchronous model allows non-blocking code execution by using callbacks and promises.

• JavaScript uses an event loop to handle asynchronous operations.

• Callbacks are functions passed as arguments to other functions and executed when the operation is complete.

• Promises are objects that represent the eventual completion or failure of an asynchronous operation.

• Async/await is a newer syntax that allows writing asyn...read more

Request lifecycle in Rails involves routing, controller actions, rendering views, and responding to the client.

• 1. Request comes in through the browser or API endpoint.

• 2. Rails router determines which controller and action to route the request to.

• 3. Controller action processes the request, interacts with the model, and prepares data for the view.

• 4. View template is rendered with the data from the controller.

• 5. Response ...read more

Implement Merge Sort algorithm in Ruby

• Divide the array into two halves recursively

• Merge the sorted halves back together

• Use a helper method to merge the two halves