Question-67. What is the primary reason for using the event-based model in Node.js?

Answer- The main reason to use the event-based model in Node.js is performance. The event-based model allows for non-blocking I/O operations, which means that Node.js can handle a large number of connections without using a lot of resources.

Question-68. What is the difference between Node.js and Ajax?

Answer- Ajax and Node.js are two different technologies that are used for different purposes. Ajax is a client-side technology that allows for asynchronous communication between the client and the server. It is typically used to update parts of a web page without requiring a full page reload.

Node.js, on the other hand, is a server-side technology that is used for building fast, scalable, and efficient server-side applications. It is typically used for real-time applications, such as chat applications, online games, and streaming services.

Question-69. What is the advantage of using Node.js?

Answer- Node.js is fast and scalable. Node.js is easy to learn and use. Node.js is well-suited for real-time applications, such as chat applications, online games, and streaming services. This is because Node.js can handle a large number of connections and can perform non-blocking I/O operations, which makes it ideal for real-time communication.

Question-70. Does Node run on Windows?

Answer- es, Node.js runs on Windows. Node.js is a cross-platform runtime environment, which means that it can run on a variety of operating systems, including Windows, macOS, and Linux.

Question-71. Can you access DOM in Node?

Answer- No, you cannot access the DOM in Node.js. The DOM is a browser-specific API that allows for the manipulation of HTML and XML documents. Since Node.js does not run in a browser, it does not have access to the DOM.

Question-72. Why is Node.JS quickly gaining attention from JAVA programmers?

Answer- Node.js is quickly gaining attention from Java programmers because it is fast, scalable, and efficient. Java is a popular server-side technology, but it can be slow and resource-intensive. Node.js, on the other hand, is built on the V8 JavaScript engine, which is known for its speed and performance.

Question-73. What are the Challenges with Node.js?

Answer- Node.js is single-threaded, which means that it can only execute one task at a time. Node.js is relatively new compared to other server-side technologies, such as Java and PHP. This means that there needs to be more support and more resources available for Node.js. Node.js is only suitable for applications that require a little memory.

Question-74. What is “non-blocking” in node.js?

Answer- In Node.js, non-blocking refers to the ability of the runtime environment to execute multiple tasks simultaneously without waiting for the completion of one task before starting the next. This is achieved through the use of asynchronous I/O operations, which allow Node.js to handle multiple requests concurrently.

Question-75. How does Node.js overcome the problem of blocking I/O operations?

Answer- Node.js uses an event-driven, non-blocking I/O model that allows it to handle I/O operations more efficiently. By using callbacks, Node.js can continue processing other tasks while waiting for I/O operations to complete. This means that Node.js can handle multiple requests simultaneously without causing any delays. Additionally, Node.js uses a single-threaded event loop architecture, which allows it to handle a high volume of requests without any issues.

Question-76. How can we use async await in node.js?

Answer- To use async/await in Node.js, you’ll need to use functions that return promises. You can then use the async keyword to mark a function as asynchronous and the await keyword to wait for a promise to resolve before continuing with the rest of the code.

Question-77. Why should you separate the Express app and server?

Answer- Firstly, separating your app and server can make it easier to test your code. By separating the two, you can test your app logic independently of the server, which can make it easier to identify and fix bugs.

Secondly, separating your app and server can make it easier to scale your application. By separating the two, you can run multiple instances of your app on different servers, which can help to distribute the load and improve performance.

Finally, separating your app and server can make it easier to switch to a different server if necessary. By keeping your app logic separate from your server logic, you can switch to a different server without having to make any major changes to your code.

Question-78. Explain the concept of stub in Node.js.

Answer- In Node.js, a stub is a function that serves as a placeholder for a more complex function. Stubs are typically used in unit testing to replace a real function with a simplified version that returns a predetermined value. By using a stub, you can ensure that your unit tests are predictable and consistent.

Question-79. What is the framework that is used majorly in Node.js today?

Answer- There are many frameworks available for Node.js, but the two most popular ones are Express and Koa.

Question-80. What are the security implementations that are present in Node.js?

Answer- One of the most important security features in Node.js is the ability to run code in a restricted environment. This is achieved through the use of a sandboxed environment, which can help to prevent malicious code from accessing sensitive data or causing any damage to the system.

Another important security feature in Node.js is the ability to use TLS/SSL to encrypt data in transit. This can help to prevent eavesdropping and ensure that sensitive data is protected.

Question-81. What is Libuv?

Answer- Libuv is a critical component of Node.js, and it’s what makes it possible to handle I/O operations in a non-blocking and efficient manner.

Question-82. What are global objects in Node.js?

Answer- Global objects in Node.js are objects that are available in all modules without the need for an explicit require statement. Some of the most commonly used global objects in Node.js include process, console, and buffer.

Question-83. Why is assert used in Node.js?

Answer- An assert module is an important tool for writing effective tests in Node.js.

Question-84. Why is ExpressJS used?

Answer- Express is a great choice for building web applications in Node.js, and its popularity and active community make it a safe and reliable choice for developers of all levels.

Question-85. What is the use of the connect module in Node.js?

Answer- The Connect module can be used to handle different types of middleware, such as error-handling middleware, cookie-parsing middleware, and session middleware. Error-handling middleware is used to handle errors that occur during the request/response cycle. Cookie parsing middleware is used to parse cookies from the request header. Session middleware is used to manage user sessions.

Question-86. What’s the difference between ‘front-end’ and ‘back-end’ development?

Answer- Front-end developers focus on the client side of the application, while back-end developers focus on the server side of the application. Both roles are important for building a successful web application and require different skill sets and expertise.

Question-87. What are LTS releases of Node.js?

Answer- LTS stands for Long-term support. LTS releases of Node.js are versions that are supported for an extended period, usually for 30 months from the time of release. These releases are typically more stable and reliable than non-LTS releases and are recommended for production use.

Question-88. What do you understand about ESLint?

Answer- ESLint is a popular open-source tool that is used to analyze and flag errors and potential problems in JavaScript code.

Question-89. Define the concept of the test pyramid. Please explain the process of implementing them in terms of HTTP APIs.

Answer- The test pyramid is a concept that is often used in software testing to illustrate the ideal distribution of different types of tests. The pyramid consists of three layers: unit tests, integration tests, and end-to-end tests. The idea is that the majority of tests should be at the unit level, with fewer tests at the integration and end-to-end levels.

To implement the test pyramid in terms of HTTP APIs, you can start by writing unit tests for each endpoint in the API. These tests should focus on testing the functionality of the endpoint in isolation without making any external requests or dependencies. Once the unit tests are passed, you can write integration tests that test the interaction between different endpoints and components in the API. Finally, you can write end-to-end tests that test the entire API, from the user interface to the database.

Question-90. How does Node.js handle the child threads?

Answer- Node.js handles child threads by creating separate instances of the Node.js runtime environment that can be used to execute code in parallel with the main process.

Question-91. What is an Event Emitter in Node.js?

Answer- An Event Emitter is a Node.js module that facilitates communication between objects in a Node.js application. It is an instance of the EventEmitter class, which provides a set of methods to listen for and emit events. In Node.js, events are a core part of the platform, and they are used to handle asynchronous operations.

Question-92. How to Enhance Node.js Performance through Clustering?

Answer- Clustering can be used to improve the performance of HTTP servers, database connections, and other I/O operations. However, it is important to note that clustering does not guarantee a linear increase in performance.

Question-93. What is a thread pool, and which library handles it in Node.js?

Answer- A thread pool is a collection of threads that are used to execute tasks in parallel. In Node.js, the thread pool is handled by the libuv library, which is a multi-platform support library that provides asynchronous I/O operations.

Question-94. How are worker threads different from clusters?

Answer- Worker threads and clusters are two different approaches to leveraging the power of multiple CPUs in Node.js. While clusters create multiple instances of a Node.js process, each running on a separate CPU core, worker threads provide a way to create multiple threads within a single process.

Question-95. How to measure the duration of async operations?

Answer- The console.time and console.timeEnd methods allow you to measure the duration of a block of code. The console.time method is used to start the timer and the console.timeEnd method is used to stop the timer and log the duration to the console.

The performance.now method provides a more precise way to measure the duration of async operations. It returns the current timestamp in milliseconds, which can be used to calculate the duration of a task.

Question-96. How to measure the performance of async operations?

Answer- There are several tools and techniques you can use to measure performance, including using the built-in –prof flag, using the perf tool, and using third-party libraries like benchmark.js.

Question-97. What are the types of streams available in Node.js?

Answer- There are four types of streams available in Node.js, including readable streams, writable streams, duplex streams, and transform streams.

Question-98. What is meant by tracing in Node.js?

Answer- Tracing is a technique used in Node.js to profile the performance of an application. It involves recording the function calls and events that occur during the execution of the application and analyzing the data to identify performance bottlenecks.

Question-99. Where is package.json used in Node.js?

Answer- The package.json file is located in the root directory of an application and it is used by the npm package manager to install and manage the dependencies of an application.

Question-100. What is the difference between readFile and create Read Stream in Node.js?

Answer- Create Read Stream is a better option for reading large files, while the read file is a better option for small files. It is important to choose the right method based on the size of the file and the requirements of the application.

Question-101. What is the use of the crypto module in Node.js?

Answer- The crypto module is widely used in Node.js applications to generate secure random numbers, create digital signatures, and verify signatures. It also provides support for various encryption algorithms such as AES, DES, and RSA.

Question-102. What is a passport in Node.js?

Answer- Passport is a popular authentication middleware for Node.js. It provides a simple and modular way to implement authentication in Node.js applications. Passport supports many authentication mechanisms, including username/password, social logins like Facebook and Google, and JSON Web Tokens (JWTs).

Question-103. How to get information about a file in Node.js?

Answer- In Node.js, the fs module provides methods for working with the file system. To get information about a file, you can use the fs. stat() method. The fs. stat() method returns an object that contains information about the file, such as the file size, creation date, and modified date.

Question-104. How does the DNS lookup function work in Node.js?

Answer- In Node.js, the DNS module provides methods for performing DNS lookups. DNS stands for Domain Name System, and it is responsible for translating domain names into IP addresses. The DNS. lookup() method is used to perform a DNS lookup and resolve a domain name into an IP address.

Question-105. What is the difference between setImmediate() and setTimeout()?

Answer- The setTimeout() method schedules code execution after a specified delay, measured in milliseconds. On the other hand, the setImmediate() method schedules code execution to occur immediately after the current event loop iteration completes. This means that setImmediate() has a higher priority than setTimeout().

Question-106. Explain the concept of Punycode in Node.js.

Answer- Punycode is a character encoding scheme used in the domain name system (DNS) to represent Unicode characters with ASCII characters. It is used to encode domain names that contain non-ASCII characters, such as Chinese or Arabic characters.

Question-107. Does Node.js provide any Debugger?

Answer- Yes, Node.js provides a built-in debugger that can be used to debug Node.js applications.

Question-108. Is cryptography supported in Node.js?

Answer- Yes, Node.js provides built-in support for cryptography through the crypto module.

Question-109. Why do you think you are the right fit for this Node.js role?

Answer- As a Node.js developer, I have experience in building scalable and efficient server-side applications using Node.js. I am a team player and have excellent communication skills. I believe that my experience and skills make me a strong candidate for this Node.js role.

Question-110. Do you have any past Node.js work experience?

Answer- Yes, my past Node.js work experience has given me a solid foundation in building scalable and efficient server-side applications using Node.js.

Question-111. Do you have any experience working in the same industry as ours?

Answer- Yes, I have worked on several Node.js projects in the past.

Question-112. Do you have any certification to boost your candidature for this Node.js role?

Answer- Yes, I am OpenJS Node. Js Services Developer (JSNSD) Certified.

Conclusion

We believe that these Node.js interview questions would help you understand what kind of questions may be asked to you in an interview, and by going through these Node.js interview questions, you can prepare and crack your next interview in one go.

[/vc_column_text][/vc_column][/vc_row]