Overview
The popular server-side platform Node.js is being used increasingly by many enterprises these days. It’s usually a smart idea to be prepared and review your interview techniques ahead of a career transition and job interview.
Along with refining your technical knowledge, wearing appropriate professional attire can leave a strong first impression during the interview process. While certain often requested Node.js interview questions arise in all kinds of interviews, we also advise you to prepare by concentrating on unique questions relevant to your particular sector.
Below is a thorough list of popular Node.js interview questions that arise frequently in interviews along with the best approaches to respond to them. This will also enable you to grasp Node.js’s fundamental concepts.
Node.js Interview Questions and Answers
The Basic Node.js interview questions in the following section will mostly benefit recent graduates.
1. What is Node.js?
Ans: Node.js is a JavaScript engine that lets you run JavaScript code in places other than browsers. Because of its scalability, it is majorly used to build the app’s backend.
2. How does Node.js manage concurrency if it operates on a single thread?
Ans: Node.js is designed for async processing and is single-threaded. Instead of using multiple threads, which are inefficient and slow under normal web traffic, executing async processing on a single thread allows for improved efficiency and scalability.
3. What is NPM?
Ans: NPM, which stands for “Node Package Manager,” is in charge of all of Node.js’s files and plugins.
Two primary features of Node Package Manager are:
- The node.js package and module repositories are accessible through the website search.nodejs.org.
- Features a command-line tool for managing versions and dependencies of Node.js as well as installing packages for the framework.
4. If Node.js is single-threaded, then how does it handle concurrency?
Ans: Adopting the single-threaded event loop model, the Node JavaScript platform does not follow the multi-threaded request/response stateless model. The JavaScript callback mechanism and JavaScript Event-based architecture greatly impact the Node JS Processing paradigm. Node.js hence can readily handle many concurrent client requests. It is the event loop in Node.js that makes the processing model work.
5. What are the two types of API functions in Node.js?
Ans: Node.js offers two kinds of API abilities:
- Asynchronous, non-blocking features.
- Synchronous, blocking features.
6. What is the difference between Node.js and JavaScript?
Ans: While Node.js is an engine offering the runtime environment to run JavaScript code, JavaScript is a programming language.
7. What are the advantages of Node.js?
Ans: The primary advantages of Node.js are as follows:
- Node.js operates asynchronously and is driven by events. All APIs in the Node.js library are non-blocking, and its server does not await the return of data from an API. It proceeds to the subsequent API following its request, while a notification system utilizing Node.js events communicates with the server regarding the prior API request.
- Node.js offers high speed due to its dependence on Google Chrome’s V8 JavaScript engine. Its library provides rapid code execution.
- Node.js operates on a single thread yet offers significant scalability.
- Node.js offers a non-buffering capability. Its program does not cache any data. It communicates the info in parts.
8. How would you define the term I/O?
Ans: The term I/O refers to any program, process, or device that facilitates the transmission of data between a medium and another medium. Each transfer represents an output from one medium and an input into the second. The medium may consist of a hardware device, a network of devices, or data in the system itself.
9. What approaches can be employed to enhance the performance of a Node.js application utilizing Express?
Ans: To enhance the speed of a Node.js (with Express) application, one can employ strategies such as caching, utilizing a load balancer, optimizing database queries, implementing compression middleware, reducing middleware consumption, and assuring non-blocking code execution.
For example, during an EHR software demo, you’ll often see how these techniques ensure real-time data handling and system reliability. Moreover, profiling and monitoring the application could possibly help the identification and removal of performance bottlenecks.
10. Explain callback in Node.js.
Ans: A callback function is executed subsequent to the completion of a specified task. It permits concurrent execution of other code and eliminates any blocking. As an asynchronous platform, Node.js primarily depends on callbacks. All Node APIs are designed to accommodate callbacks.
11. What is the definition of event-driven programming?
Ans: An event-driven programming approach utilizes events to activate several functionalities. An event may include any activity, such as using a keyboard or pressing the mouse key. A callback function is already registered with the element and executes anytime an event is triggered.
12. Which database is usually utilized with Node.js?
Ans: MongoDB is the predominant database utilized with Node.js. It is a NoSQL, cross-platform, document-centric database that offers superior performance, exceptional availability, and effortless scalability.
13. What is an Event Loop in Node.js?
Ans: Event loops manage asynchronous callbacks in Node.js. It is the most important environment components of Node.js since it is the basis of the non-blocking input/output.
14. How do you handle real-time communication in a Node.js application?
Ans: Real-time communication in a Node.js application is usually made easier by Socket.IO, a framework that allows for bidirectional and event-driven communication between clients and servers. Socket.IO operates on WebSockets while simultaneously offering fallbacks for old browsers without WebSocket capability.
To establish real-time communication, it is essential to install Socket.IO and configure it on both the server and client sides. The server initiates a WebSocket connection, monitors client events, and can transmit events to clients. Besides establishing a connection to the server, the client, often a connected to the web browser, interacts with it via events.
15. Explain the difference between SQL and NoSQL databases. What is the method by which Node.js establishes connections with them?
Ans: SQL databases are connected and organized and use SQL for data definition and manipulation. NoSQL databases are non-relational which include dynamic schemas, and are utilized for extensive collections of scattered data. Node.js interfaces with SQL databases with libraries such as pg for PostgreSQL and MySQL for MySQL, while it connects to NoSQL databases like MongoDB using libraries such as Mongoose.
