VVDN Technologies Node JS Developer Interview Questions and Answers

Q1. What is nodejs, explain the event loop.
Ans. 
Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. It allows developers to run JavaScript on the server-side.
• Node.js is event-driven and non-blocking I/O model.

• It uses an event loop to handle asynchronous operations.

• The event loop is a continuously running process that waits for events and executes callbacks.

• Callbacks are functions that are called when an event occurs, such as a request completing ...read more
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Q2. What is event loop ?
Ans. 
Event loop is a mechanism that allows Node.js to perform non-blocking I/O operations.
• Event loop is a single-threaded loop that constantly checks for new events in the event queue.

• It executes the callback functions associated with the events in the queue.

• It allows Node.js to handle multiple requests simultaneously without blocking the execution of other requests.

• It is responsible for managing the order of execution of t...read more
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Q3. What is the role of libuv ?
Ans. 
libuv is a multi-platform support library with a focus on asynchronous I/O.
• libuv provides event loop, thread pool, timer, and file system APIs.

• It is used by Node.js to handle I/O operations in a non-blocking way.

• libuv abstracts the differences between operating systems and provides a consistent API.

• It also supports network programming and inter-process communication.

• Examples of libuv-based applications include Node.js,
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Q1. What is the difference between cluster and thread ?
Ans. 
Cluster is a group of processes that share the same resources while thread is a lightweight process that shares the same memory.
• Cluster is used for scaling and load balancing while thread is used for improving performance.

• Cluster can run on multiple machines while thread runs within a single process.

• Cluster requires inter-process communication while thread does not.

• Examples of cluster include PM2 and Node.js cluster mo...read more
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Codility- Angular - 2 questions, complete code for html, ts files

Q1. SOLID principles
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Q2. Prototypes with examples, create a prototype that removes duplicate words from a sentence
Ans. 
Prototype to remove duplicate words from a sentence using an array of strings
• Create a function that takes in a sentence as input

• Split the sentence into an array of words

• Use a Set data structure to store unique words

• Iterate through the array of words and add each word to the Set

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

• Join the unique words back into a sentence
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Q3. Union types and intersection Types
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Q4. Utility types- Omit and Partial
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Q5. Angular Change Detection
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Q6. ZoneJS and Signals
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Q7. ViewChild and ViewChildren
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Q8. View Encapsulation
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Q9. Subject and Behaviour Subject
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Q10. Dynamic Component Loading
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Q11. MergeMap and SwitchMap
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Q12. Performance tuning in Angular
Ans. 
Performance tuning in Angular involves optimizing code, reducing load times, and improving user experience.
• Use lazy loading to load modules only when needed

• Minimize the number of HTTP requests by combining files and using caching

• Optimize change detection by using OnPush strategy

• Avoid unnecessary DOM manipulations and use trackBy function in ngFor loops

• Use AOT compilation to reduce bundle size and improve load times
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Q1. The 1st round was JAM - Just a minute. They will give you a topic on the spot and we have to talk about this topic for 1-2min. Topics: The perfect prank you pulled, The best trip, Your pet's inner thoughts...read more
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The 2nd round is GD: The GD was conducted properly for other batches. But for our batch the HR just collected everyone's resume and asked qns from our resume.
(Note: This is not an elimination round)

The 3rd round was Aptitude and Technical mcq test: 10 qns - DBMS, 20 - Quants, 20 - Java mcq
(Note: This round has negative markings)

Q1. Resume based and about projects
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Q2. Basic sql queries Eg: SQL query to find the no of students in a department
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Q3. Reverse a string - Python
Ans. 
Reverse a string in Python using slicing
• Use string slicing with a step of -1 to reverse the string

• Example: 'hello'[::-1] will return 'olleh'
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Q1. The last round was general hr: Since there were two many candidates the process took too much time. There was no questions asked during the hr round, who ever has agreed to the 2yrs bond were recruited
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Q1. Core java oops concepts
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Q2. Angular basic topics
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Q1. Spring boot topics
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Q2. Oracle queries examples
Ans. 
Examples of Oracle queries
• Use SELECT statement to retrieve data from a table

• Use WHERE clause to filter results based on a condition

• Use JOIN to combine rows from two or more tables based on a related column
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Q1. Discussed about my carrer details
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Q2. Expected CTC discussed
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Q1. Basic questions on dotnet core
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Q2. Basic questions on angular
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MCQ asked for css,js etx

Q1. Ask for basic dot net questions
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Quantitative , figure ,mcq question based on tech stack and 2 coding question which are basic. 90 minute time limit.

Q1. Angular question
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Q2. .net question and sql question
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Quants, Reasoning and Verbal
Computer fundamental and pseudocode

15 mins with general topics

Q1. What do like in your college the most?
Ans. 
I enjoyed the collaborative projects and hands-on learning experiences in my college.
• Collaborating with classmates on coding projects

• Hands-on experience with different programming languages

• Engaging discussions in computer science classes
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Q2. Do you have any other offer?
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