Octal IT Solution Node JS Developer Interview Questions and Answers

BE AWARE THAT Interview starts at 10 ends at 6 in the evening

this will be 1st round

let arr=[{id:1,x:10},{id:2,y:10}}],let arr2=[{id:1:x10},{id:3,y:20}]
you need to combine both the object merge it into one

2. you will be given sql query to write that is get method

Q1. How node.js works
Ans. 
Node.js is a runtime environment that allows JavaScript code to run on the server-side.
• Node.js uses an event-driven, non-blocking I/O model, making it lightweight and efficient.

• It uses the V8 JavaScript engine from Google Chrome to execute code.

• Node.js allows developers to build scalable network applications using JavaScript.

• It has a large ecosystem of libraries and frameworks, such as Express.js for web applications.
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Q2. What is event loop in Node.js
Ans. 
Event loop in Node.js is a mechanism that allows Node.js to perform non-blocking I/O operations.
• Event loop is responsible for handling asynchronous operations in Node.js.

• It allows Node.js to perform multiple operations concurrently without blocking the execution.

• Event loop continuously checks the event queue for any pending events and executes them in a loop.

• Example: When reading a file in Node.js, the event loop allow...read more
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Q1. How to deploy node.js application
Ans. 
Node.js applications can be deployed using various methods such as using a hosting service, containerization, or serverless platforms.
• Use a hosting service like Heroku, AWS, or DigitalOcean to deploy the application.

• Containerize the application using Docker and deploy it on a container orchestration platform like Kubernetes.

• Utilize serverless platforms like AWS Lambda or Google Cloud Functions for deploying serverless
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Q2. List AWS services used
Ans. 
Some AWS services commonly used by Node JS developers are EC2, S3, Lambda, RDS, and API Gateway.
• EC2 (Elastic Compute Cloud) for scalable virtual servers

• S3 (Simple Storage Service) for object storage

• Lambda for serverless computing

• RDS (Relational Database Service) for managed databases

• API Gateway for creating, publishing, maintaining, monitoring, and securing APIs
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Q1. Tell me about yourself. Tell me about your project and technical background What project you have done . Technology? Which AWS services you have used tell me about AWS lambda function How to make aws lamb...read more
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Q2. When did you used and where did you used redis cache
Ans. 
I have used Redis cache in multiple projects to improve performance and reduce database load.
• Used Redis cache to store frequently accessed data for faster retrieval

• Implemented Redis cache in a Node.js application to cache API responses

• Utilized Redis cache to store session data for improved user experience
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Q1. What is the reason data didnt reached backend
Ans. 
Possible reasons for data not reaching backend include network issues, incorrect API endpoints, server errors, and client-side validation errors.
• Network connectivity issues

• Incorrect API endpoints

• Server errors

• Client-side validation errors
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Q2. How to scale app for more users
Ans. 
To scale an app for more users, consider optimizing code, using caching, load balancing, and horizontal scaling.
• Optimize code for better performance

• Implement caching to reduce database load

• Use load balancing to distribute traffic evenly

• Consider horizontal scaling by adding more servers

• Use microservices architecture for better scalability
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Q1. All basic question related to node.js like event loop,
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Q2. What is event loop?
Ans. 
Event loop is a mechanism in node.js that allows non-blocking I/O operations by handling asynchronous tasks efficiently.
• Event loop is responsible for handling asynchronous operations in node.js.

• It allows node.js to perform non-blocking I/O operations by delegating tasks to the operating system.

• Event loop continuously checks the event queue for new tasks and executes them in a loop.

• It helps in preventing the blocking of...read more
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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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Q1. Wht do you know about your company
Ans. *Do a proper research about the company *Read online about the company's latest Abdates *understand it's business *role thoroughly the job description
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Q2. Why should we hear you?
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Q3. With this tricky interview questions amd answer the employer wants to see your ability to pitch your skills and conversing power.
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Q1. What are your strengths and weaknesses?
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Q2. Tell me about self details
Ans. First i would like to for giving me this wonderful opportunity my self sobha i am from kadapa i have completed graduate in BSC biotechnology in vaishnavi degree college in rajampet. Percentage is 80%. I have 5 members are my family. I do have certificate in various department of clinical research amd clinical trials. My strength or quick Lerner dedicated towards assessment i have good exposure in clinical data mana
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Q3. What is Pharmacovilance
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Q4. Pharmacoviglance is a science is related to detection assessment understanding prevention of adverse events.
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Q5. What clinical research?
Ans. 
I'm sorry, but the question is not related to the job position of Node JS Developer.
• The question is not relevant to the job position.

• It is important to stay focused on the job requirements.

• If you are unsure about a question, it is okay to ask for clarification.
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Q6. Clinical research is a branch of health care science that determines the safety and effectiveness of medications devises diagnostic products treatment regiment intended from human use.
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Q1. What is event loop
Ans. 
Event loop is a mechanism in Node.js that allows non-blocking I/O operations to be performed asynchronously.
• Event loop is responsible for handling asynchronous operations in Node.js

• It allows Node.js to perform I/O operations without blocking the execution of other code

• Event loop continuously checks the event queue for new events to process

• Callbacks are used to handle the completion of asynchronous operations
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Q2. What is api gateway in aws
Ans. 
API Gateway in AWS is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs at any scale.
• API Gateway allows you to create RESTful APIs that can be integrated with other AWS services like Lambda, DynamoDB, and S3.

• It provides features like authentication, authorization, rate limiting, and caching to improve API performance and security.

• API Gateway can also be use...read more
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Q3. What's swagger and how to add authentication in swagger
Ans. 
Swagger is a tool for designing, building, and documenting APIs. Adding authentication in Swagger involves using security definitions and security requirements.
• Swagger is a tool used for designing, building, and documenting APIs

• To add authentication in Swagger, you can use security definitions to define authentication methods like API keys, OAuth, etc.

• You can then specify security requirements in your Swagger documenta...read more
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