Top 30+ Node js Interview Questions and Answers for 2024

The event loop is responsible for handling and dispatching events, such as I/O operations, timers, and callbacks. Node JS processes these events one after another, and it doesn’t wait for the operation to complete when there are I/O operations, such as reading a file or querying a database. It delegates the operation, proceeds with the event loop, and gets notified once the operation is done. This mechanism ensures that Node JS keeps executing other code without being held up, achieving its asynchronous behavior.

What are Promises and How Do They Improve Asynchronous Programming?

• This can present an opportunity to delve into best practices in API design, such as versioning and documentation strategies.
• This design allows it to handle multiple tasks simultaneously, such as processing user requests or fetching data from a database, without waiting for one task to finish.
• The ‘fs’ module offers the writing and reading files and it provides an API for working with the file systems.
• When running test cases, stubs are useful in providing the details of the functions executed.
• Modules are like JavaScript libraries that can be used in a Node.js application to include a set of functions.

There are numerous benefits to using it, such as improved application performance and enhanced responsiveness. Async provides lots of powerful utilities to work with asynchronous processes under different scenarios. Async is a really powerful npm module for managing asynchronous nature of JavaScript. Along with Node.js, it also works for JavaScript written for browsers. Core modules are always preferentially loaded if their identifier is passed to require().

What is a CMS (Content Management System)?

It uses an event-driven, non-blocking I/O model that allows multiple operations to be processed simultaneously. Node.js extensively utilizes callbacks, invoking them upon the conclusion or completion of a specific task. ReactJS is a popular JavaScript library for creating user interfaces (UIs) of web applications.

🔄 Explain lifecycle methods in React.

While developing React applications, we might develop components that are quite similar to each other with minute differences. We can say that props are the data passed from a parent component into a child component. One of them is used to store the current state of the objects and the other to store the previous state of the objects. Whenever the virtual DOM gets updated, react compares the two virtual DOMs and gets to know about which virtual DOM objects were updated.

It happens when you have a lot of callbacks inside callbacks, making the code difficult to understand, read, and update. Deeply nested callback functions result when working with asynchronous actions, such as managing events or submitting API calls, when one activity depends on the result of another. Now that you have learned about all the potential full-stack developer interview questions and answers, let us look at some of the most essential tips to ace the interview.

Q3. What is the purpose of a pull request?

• Revinate provides guest experience and reputation management solutions for the hospitality industry.
• Asynchronous methods like ‘fs.readFile’ and ‘fs.writeFile’ are designed to execute without freezing the event loop, ensuring that server responsiveness remains intact.
• For more elaborative interview preparation, check out our guide on the Node.js interview questions.
• The package.json file is located in the root directory of an application and the npm package manager uses it to install and manage the dependencies of an application.
• Familiarity with ES6 modules is critical, especially with their growing adoption in contemporary projects.
• Responses to any previous requests will be continuous, even if the server has already gotten the response.

Limit logging levels and consider asynchronous logging mechanisms to minimize synchronous I/O blocking. Database queries may often act as bottlenecks if they are not optimized. Monitoring tools like New Relic or DataDog can provide insights into query performance. Utilizing `require` programmer and `import` serves the purpose of including modules in a project, yet their usage diverges in syntax and behavior, particularly post-ES6 introduction which promoted modules. According to the US Bureau of Labor Statistics (BLS), web developers earn a median salary of $95,380 1. Ensuring fast load times is critical for high conversion rates and revenue generation through your website.

Explain Spring Data and What is Data JPA?

You can start your application with the –inspect flag, which opens a debugging session on a given port. In Node.js, errors can be handled using several techniques, depending on the type of error and the context in which it occurs. JavaScript is typically executed within a web browser, while Node.js is executed on the server side. A library for working with dates and times in JavaScript, which provides a simple and flexible way to parse, manipulate, and format dates and times. A promise library that provides a fast and feature-rich implementation of promises in JavaScript. Node.js is a very versatile platform that can be used with many different types of databases.

It is very important to follow resource management best practices to avoid connection leaks. In the example, “use strict” prevents the unintentional creation of global variables, helping to catch potential bugs early. The test pyramid is a figure that explains the specific proportion of various components in Node.js like JavaScript Full-stack developer (Node.jsReact.js) job unit tests, integration tests, and end-to-end tests. Buffer class is used to store raw data mainly because pure JavaScript is not compatible with binary data.

• A utility library that provides functions for working with asynchronous JavaScript, such as handling callbacks, promises, and control flow.
• When a module is loaded with the required function in Node.js, the module.exports object is returned to the caller, providing access to the public interface of the module.
• BSON (Binary JSON) is a binary-encoded serialization format used by MongoDB to store documents.
• Four types of streams are available in Node.js, including readable, writable, duplex, and transform streams.
• The createReadStream process is partially buffered, treating the entire process as a series of events.
• Middleware chaining refers to passing control from one middleware function to the next using the next() function.

Lango is a full-service language access company with over 60 years of combined experience and offices across the US and globally. Lango enables organizations in education, healthcare, government, business, and legal to support their communities with a robust language access plan. The assert module is used for simple checks of situations using conditions, i.e. it is used for assertation. That is most helpful when you have function tests or when you are expecting something in the outcome of a function. The web server can use X-XSS-Protection response header to make sure pages do not load when they detect reflected cross-site scripting (XSS) attacks.