20+ Infosys Node JS Developer Interview Questions and Answers

Nodejs application can be deployed using various tools like Heroku, AWS, DigitalOcean, etc.

• Use a cloud platform like Heroku, AWS, DigitalOcean, etc.

• Create a production build of the application

• Configure environment variables

• Use a process manager like PM2 to manage the application

• Use a reverse proxy like Nginx to handle incoming requests

• Set up SSL/TLS certificates for secure communication

Yes, I follow agile methodology for software development.

• I believe in iterative development and continuous feedback.

• I prioritize customer satisfaction and collaboration with the team.

• I use tools like Jira and Trello to manage tasks and sprints.

• I also follow the Scrum framework for daily stand-ups, sprint planning, and retrospectives.

Error first callback function is a convention in Node.js where the first parameter of a callback function is reserved for an error object.

• The error object is passed as the first argument to the callback function

• If there is no error, the error object will be null or undefined

• If there is an error, the error object will contain information about the error

• This convention allows for consistent error handling in asynchronous operations

• Example: fs.readFile(path, 'utf8', function(err...read more

The setTimeout function in JavaScript is used to schedule a task to be executed after a specified delay.

• The setTimeout function takes two parameters: a callback function and a delay time in milliseconds.

• The callback function is executed after the specified delay.

• The setTimeout function returns a unique identifier (timer ID) that can be used to cancel the execution of the callback function using the clearTimeout function.

• The output of the setTimeout function itself is not sign...read more

To connect to MongoDB from NodeJS backend, use the 'mongodb' package and the 'MongoClient' class.

• Install the 'mongodb' package using npm: npm install mongodb

• Require the 'mongodb' package in your NodeJS file: const MongoClient = require('mongodb').MongoClient

• Create a connection URL with the appropriate MongoDB server details: const url = 'mongodb://localhost:27017/mydatabase'

• Use the 'MongoClient' class to connect to the MongoDB server: MongoClient.connect(url, function(err, db...read more

SQL command to get the TOP 3 list in a data set

• Use the SELECT statement to retrieve data from the table

• Use the ORDER BY clause to sort the data in descending order

• Use the LIMIT clause to limit the result set to 3 rows

I implemented Docker and Kubernetes to containerize and orchestrate my NodeJS applications.

• I used Docker to create containers for my NodeJS applications, ensuring consistency and portability.

• I wrote Dockerfiles to define the environment and dependencies for each application.

• I used Docker Compose to define and manage multi-container applications.

• I used Kubernetes to orchestrate and manage the deployment, scaling, and monitoring of my NodeJS applications.

• I created Kubernetes de...read more

Node.js is a runtime environment for executing JavaScript code outside of a web browser.

• Node.js is built on the V8 JavaScript engine, while JavaScript is a programming language.

• Node.js allows JavaScript to be run on the server-side, while JavaScript is primarily used for client-side scripting.

• Node.js provides additional features and APIs for server-side development, such as file system access and networking capabilities.

• JavaScript is used for web development, creating interac...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 documentation to enforce authentication for specific endpoints

• For e...read more

Functional components are stateless and use functional syntax, while class components have state and lifecycle methods.

• Functional components are simpler and easier to read/write.

• Class components have access to lifecycle methods like componentDidMount.

• Functional components do not have access to state or lifecycle methods.

• Functional components can use hooks like useState and useEffect to manage state and side effects.

• Example: Functional component - const MyComponent = () => { r...read more

Nodejs is a JavaScript runtime built on Chrome's V8 JavaScript engine.

• Nodejs uses an event-driven, non-blocking I/O model.

• It is designed to build scalable network applications.

• Nodejs uses modules to organize code.

• It has a built-in package manager called npm.

• Nodejs can be used for both server-side and client-side programming.

A callback function in NodeJS is a function that is passed as an argument to another function and is executed later.

• Callback functions are commonly used in asynchronous programming in NodeJS.

• They allow us to handle the result of an asynchronous operation once it is completed.

• Callback functions can be defined inline or as separate named functions.

• They are often used with functions like setTimeout, readFile, and database queries.

• Callback functions can accept parameters to pass ...read more

OAuth is an open standard for authorization that allows users to grant access to their data without sharing their credentials.

• OAuth is used to authenticate and authorize users in applications.

• It allows users to grant limited access to their data to third-party applications.

• OAuth uses tokens to grant access instead of sharing credentials.

• The OAuth flow involves the client, server, and the authorization server.

• Popular OAuth providers include Google, Facebook, and Twitter.

Nodejs is a server-side runtime environment while Angularjs is a client-side JavaScript framework.

• Nodejs is used for building server-side applications while Angularjs is used for building client-side applications.

• Nodejs is based on JavaScript and uses an event-driven, non-blocking I/O model.

• Angularjs is a framework for building dynamic web applications using HTML, CSS, and JavaScript.

• Nodejs is used for creating APIs, handling requests, and managing databases.

• Angularjs is used...read more

Redux is a predictable state container for JavaScript apps. Redux Toolkit is the official, recommended way to write Redux logic.

• Redux is a state management library for JavaScript applications, commonly used with React.

• It helps in managing the state of an application in a predictable way.

• Redux Toolkit is the official, recommended way to write Redux logic, providing utilities to simplify common Redux use cases.

• It includes functions like 'createSlice' for defining Redux state sl...read more

Terraform is used to automate infrastructure provisioning and management.

• Terraform is a tool for defining and provisioning infrastructure as code.

• It allows you to create, modify, and destroy infrastructure resources using declarative configuration files.

• Terraform supports various cloud providers like AWS, Azure, and GCP.

• You can define infrastructure resources such as virtual machines, networks, and storage using Terraform's domain-specific language (DSL).

• Terraform provides a ...read more

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 used to transform and proxy requests to different backend ser...read more

AWS Mesh is a service mesh that provides secure communication between microservices in a containerized application.

• AWS Mesh is built on top of AWS App Mesh, which is a managed service for service mesh architecture.

• It allows developers to easily monitor and control the communication between microservices.

• AWS Mesh provides features like traffic routing, load balancing, service discovery, and observability.

• It supports various protocols and platforms, including Node.js applicatio...read more

API is a set of rules and protocols for building and interacting with software applications. Schema defines the structure of data in a database.

• API stands for Application Programming Interface, it defines how software components should interact.

• APIs can be used to access data or functionality from external sources, such as a web server or database.

• Schema defines the structure of data in a database, including tables, fields, and relationships.

• Schema can be used to enforce data...read more