Safari Company Interview Questions and Answers

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 Node.js 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 allows other operations to continue while waiting for the file ...read more

Use a database driver like Mongoose or Sequelize to connect a database to Node.js

• Install the database driver package using npm

• Require the database driver in your Node.js application

• Create a connection to the database using the driver's connection method

• Use the connection object to interact with the database

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

Callback hell is a situation in asynchronous JavaScript programming where multiple nested callbacks make the code difficult to read and maintain.

• Occurs when multiple asynchronous operations are nested within each other

• Leads to deeply nested code structure which is hard to read and debug

• Can be avoided by using promises, async/await, or modularizing code

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.

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

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