Interview Questions of Node JS And MongoDB

  • By Sonal Vanarse
  • April 1, 2024
  • JavaScript
Interview Questions of Node JS And MongoDB 

Interview Questions of Node JS And MongoDB

Prepare for Interview Questions of Node JS and MongoDB with SevenMentor’s latest blog. Get expert guidance and boost your confidence for success!

What is Node.js?

    • Node.js is an open-source, server-side JavaScript runtime environment built on Chrome’s V8 JavaScript engine. It allows developers to run JavaScript code on the server side, enabling non-blocking, event-driven I/O operations, and scalable network applications.

What are the key features of Node.js?

    • Asynchronous and event-driven: Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient for handling concurrent requests.
    • Single-threaded but highly scalable: Node.js employs a single-threaded event loop architecture, which enables it to handle multiple concurrent connections efficiently.
    • Extensive npm ecosystem: Node Package Manager (npm) provides access to a vast ecosystem of open-source libraries and modules, allowing developers to easily extend Node.js functionality.
    • Cross-platform: Node.js is platform-independent and runs on various operating systems such as Windows, macOS, and Linux.

What is npm?

    • npm (Node Package Manager) is the default package manager for Node.js, used to install, manage, and share packages of JavaScript code. It consists of a command-line client and an online repository of public and private packages.

What is a callback function in Node.js?

    • In Node.js, a callback function is a function that is passed as an argument to another function and is executed after the completion of a specific task or operation. Callbacks are commonly used in asynchronous programming to handle I/O operations or events.

What is the event loop in Node.js?

    • The event loop is the core mechanism in Node.js that handles asynchronous operations and event-driven programming. It continuously checks for events and executes callback functions in response to events such as I/O operations, timer events, and incoming requests.

Explain the difference between blocking and non-blocking I/O in Node.js.

    • Blocking I/O operations are synchronous, meaning the execution of code is halted until the operation completes. In contrast, non-blocking I/O operations are asynchronous, allowing the program to continue executing other tasks while waiting for I/O operations to complete. Node.js utilizes non-blocking I/O to achieve high concurrency and performance.

What is Express.js?

    • Express.js is a minimalist, flexible web application framework for Node.js, designed for building web applications and APIs. It provides a robust set of features for routing, middleware, templating, and handling HTTP requests and responses.

How do you handle errors in Node.js?

    • Errors in Node.js can be handled using try-catch blocks for synchronous code and error-first callbacks or Promise.catch() for asynchronous code. Additionally, middleware functions in frameworks like Express.js can be used for error-handling middleware.


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What is middleware in Express.js?

    • Middleware functions in Express.js are functions that have access to the request and response objects in the application’s request-response cycle. They can perform tasks such as logging, authentication, data parsing, and error handling, and can be chained together to process requests in sequence.

How do you create a simple HTTP server in Node.js?

  1. const http = require(‘http’);
  2. const server = http.createServer((req, res) => {
  3.     res.writeHead(200, {‘Content-Type’: ‘text/plain’});
  4.     res.end(‘Hello, World!\n’);
  5. });
  6. server.listen(3000, () => {
  7.     console.log(‘Server running at http://localhost:3000/’);


Interview Questions of API:

What is an API?

What are the types of APIs?

    • There are several types of APIs, including:
      • Web APIs (RESTful APIs)
      • SOAP APIs
      • RPC (Remote Procedure Call) APIs
      • Library-based APIs
      • Hardware APIs

What is the difference between an API and a library?

    • An API is a set of rules and protocols that allows different software applications to communicate with each other. A library, on the other hand, is a collection of pre-written code that can be reused by other software applications to perform specific tasks.

What is the role of HTTP in APIs?

    • HTTP (Hypertext Transfer Protocol) is commonly used as the underlying protocol for communication in web APIs. It defines the rules for sending and receiving requests and responses between clients and servers over the internet.

What is the difference between a public API and a private API?

    • A public API is accessible to external developers and third-party applications, allowing them to interact with a service or platform. A private API, on the other hand, is intended for internal use within an organization and is not exposed to external users.


Interview Questions of REST API :

What is REST?

    • REST stands for Representational State Transfer. It is an architectural style for designing networked applications, particularly web services, that uses standard HTTP methods (GET, POST, PUT, DELETE) and adheres to stateless communication principles.

What are the characteristics of RESTful APIs?

    • The key characteristics of RESTful APIs include:
      • Client-server architecture
      • Stateless communication
      • Uniform interface (resource-based, self-descriptive messages, hypermedia as the engine of application state)
      • Cacheability
      • Layered system
      • Code on demand (optional)

What are HTTP methods commonly used in RESTful APIs?

    • The common HTTP methods used in RESTful APIs are:
      • GET: Retrieve a resource
      • POST: Create a new resource
      • PUT: Update an existing resource
      • DELETE: Delete a resource

What is the purpose of HTTP status codes in RESTful APIs?

    • HTTP status codes indicate the result of a client’s request to the server. They provide information about the success, failure, or status of the request, such as 200 OK (success), 404 Not Found (resource not found), or 500 Internal Server Error (server error).


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What is the difference between PUT and POST in RESTful APIs?

    • PUT is used to update an existing resource, while POST is used to create a new resource. PUT requests are idempotent, meaning that making the same request multiple times will have the same effect as making it once. POST requests are not idempotent.

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Sonal Vanarse

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