Zummit Infolabs Node JS Developer Interview Questions and Answers

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.

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

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

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

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

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

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

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

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.

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

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

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

A callback function is a function passed as an argument to another function, which will be executed at a later time.

• Used in asynchronous programming to handle tasks that take time to complete

• Allows functions to be executed after another function has finished

• Commonly used in Node.js for handling I/O operations

setTimeout function in JavaScript executes a function after a specified delay.

• setTimeout function takes two parameters: a function to be executed and a delay in milliseconds.

• The function is executed only once after the specified delay.

• Example: setTimeout(() => { console.log('Hello, World!'); }, 2000); // Output: 'Hello, World!' after 2 seconds