VELOTIO Technologies Interview Questions and Answers

Q1. What is hoisting
Ans. 
Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during compilation.
• Variable declarations are hoisted to the top of their scope but not their initializations.

• Function declarations are fully hoisted, meaning they can be called before they are declared.

• Hoisting can lead to unexpected behavior if not understood properly.
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Q2. What is throttling
Ans. 
Throttling is a technique used to control the rate at which a function is executed.
• Throttling limits the number of times a function can be called over a specified period of time.

• It helps in optimizing performance by preventing excessive function calls, especially in scenarios like scroll events or API requests.

• Example: Throttling can be used to limit the rate at which a user can resize a window, ensuring smoother perfo...read more
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Q3. What is debouncing
Ans. 
Debouncing is a technique used to limit the number of times a function is called in a short period of time.
• Debouncing is often used in scenarios like search bars where you want to wait for the user to finish typing before making an API call.

• It involves setting a delay before executing a function after the last time it was called.

• Debouncing helps in optimizing performance by reducing unnecessary function calls.

• Example: ...read more
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Q4. What is event coupling
Ans. 
Event coupling is the dependency between different parts of a system based on events.
• Event coupling occurs when one component triggers an event that another component listens for.

• It can lead to tight coupling between components, making the system harder to maintain.

• Reducing event coupling can be achieved by using a centralized event bus or implementing a pub/sub pattern.

• Example: A button click event in a UI component t...read more
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Q5. Remove duplicates from array
Ans. 
Use Set to remove duplicates from array of strings
• Create a Set from the array to automatically remove duplicates

• Convert the Set back to an array to get unique values

• Example: const arr = ['apple', 'banana', 'apple', 'orange']; const uniqueArr = [...new Set(arr)];
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Q6. Reverse a Linked List
Ans. 
Reverse a linked list by changing the direction of pointers
• Create three pointers: prev, current, next

• Iterate through the linked list, updating pointers to reverse the direction

• Return the new head of the reversed linked list
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Q7. Explain closure function with an example
Ans. 
Closure function is a function defined inside another function, with access to the outer function's variables.
• Closure functions have access to the outer function's variables even after the outer function has finished executing.

• They can be used to create private variables and functions in JavaScript.

• Example: function outerFunction() { let outerVar = 'I am outer'; function innerFunction() { console.log(outerVar); } retur...read more
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Q1. Javascript Coding test Med level
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Q1. Technical questions
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Q1. They asked questions on Data Structures & Algorithms (DSA), problem-solving, and Ruby on Rails (RoR).
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Q2. What types of coding challenges and conceptual questions were included in the interview related to Ruby on Rails (RoR) development?
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Questions were around Javascript, React and basic pragmatic coding round

Q1. What are promises.
Ans. 
Promises are objects representing the eventual completion or failure of an asynchronous operation.
• Promises are used in JavaScript to handle asynchronous operations.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained together using .then() to handle success and failure.

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

• Example: Fetching data from an API returns...read more
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Q2. What are event loop.
Ans. 
Event loop is a mechanism in programming that allows for asynchronous execution of code by continuously checking for and handling events.
• Event loop is commonly used in JavaScript to handle asynchronous operations like setTimeout, setInterval, and AJAX requests.

• It allows for non-blocking I/O operations, ensuring that the program can continue running while waiting for I/O operations to complete.

• Event loop works by contin...read more
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Small algorigthmic problem