Node.js is a powerful open-source runtime environment built on Chrome's V8 JavaScript engine. It allows developers to run JavaScript code outside of a browser, enabling server-side scripting and building scalable, high-performance web applications. With its non-blocking, event-driven architecture, Node.js efficiently handles concurrent requests and performs well with real-time applications. It provides a vast ecosystem of modules through npm (Node Package Manager) that facilitates code reusability and accelerates development. Node.js has gained popularity for its ability to handle heavy I/O operations and enables JavaScript developers to build server-side applications with ease.
NodeJs Interview Questions:
When preparing for a Node.js interview, it's essential to familiarize yourself with common interview questions on nodejs to confidently showcase your knowledge and skills. Here is an introduction to the top 15 Node.js interview questions:
1. 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, enabling the development of scalable and high-performance web applications.
2. What is npm?
npm (Node Package Manager) is the default package manager for Node.js. It is used to install, manage, and share reusable JavaScript code packages/modules with ease.
3. 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 gets executed once the latter completes its task. It allows handling asynchronous operations in Node.js effectively.
4. What is an event loop in Node.js?
The event loop is a crucial component of Node.js that handles asynchronous operations. It continuously checks for pending events and executes the associated callback functions, ensuring non-blocking and efficient execution.
5. What is the difference between JavaScript and Node.js?
JavaScript is a programming language that can run on both the client-side (browser) and server-side (Node.js). Node.js, on the other hand, is a runtime environment that allows executing JavaScript code on the server-side.
6. What are the core modules in Node.js?
Node.js provides several built-in core modules that offer essential functionalities. Some examples include 'http' for creating HTTP servers, 'fs' for file system operations, and 'path' for working with file paths.
7. What is the purpose of the 'package.json' file in Node.js?
The 'package.json' file is used to describe a Node.js project's metadata and dependencies. It includes information about the project, its dependencies, scripts, and other details required for managing the project.
8. How can you handle errors in Node.js?
In Node.js, errors can be handled using try-catch blocks, error event listeners, or by propagating errors to the caller through callback functions.
9. What is the purpose of the 'require()' function in Node.js?
The 'require()' function is used to import and use external modules in Node.js. It enables code reusability and modularization.
10. What is Express.js?
Express.js is a popular web application framework for Node.js. It provides a set of features and tools for building web applications, such as routing, middleware support, and template engine integration.
11. What is middleware in Express.js?
Middleware functions in Express.js are functions that can access the request and response objects, modify them, and execute additional code. They are used to perform tasks like authentication, error handling, logging, etc.
12. How can you handle form data in Node.js?
To handle form data in Node.js, you can use the 'body-parser' middleware package, which parses the incoming request body and makes it accessible in the 'req.body' object.
13. What is the difference between 'res.send()' and 'res.json()' in Express.js?
'res.send()' is used to send a response with any content-type, while 'res.json()' specifically sends a JSON response. 'res.json()' automatically sets the 'Content-Type' header to 'application/json'.
14. How can you connect to a database in Node.js?
Node.js provides various modules for connecting to databases. For example, 'mysql' for MySQL, 'mongodb' for MongoDB, and 'pg' for PostgreSQL. These modules allow establishing connections, executing queries, and handling database operations.
15. How can you handle file uploads in Node.js?
For file uploads, you can use middleware like 'multer' in Node.js. 'multer' simplifies the handling of multipart/form-data, enabling easy uploading and processing of files in the server.
Remember, understanding these Nodejs interview questions and their answers will give you a solid foundation for Node.js interviews. However, it's always beneficial to dive deeper into the topics and explore further resources to enhance your knowledge and understanding of Node.js.
Preparing for these interview questions will give you a solid foundation to showcase your understanding of Node.js concepts, best practices, and practical application. Remember to not only memorize the answers but also understand the underlying concepts to provide clear and concise responses during the interview.
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