Due to Node.js’s amazing capabilities and performance, top organisations use it extensively. This article contains 20+ Node.js exam questions with answers that are suitable for both newbies and experienced professionals.
Node.JS Interview Questions and Answers for Freshers
1. What is Node.js?
A JavaScript engine dubbed Node.js executes JavaScript code without a browser. It’s flexible and usually utilized to create the backend of an application.
2. What exactly does the term Javascript first-class function mean?
First-class functions are the ones which can be used just like other variables. Many other programming languages are like this including JavaScript, Scala, Haskell etc.
Because of this function, the function is now able to be able to return a higher-order function or be an argument to the callback function. Most commonly, higher-order functions include the map() as well as filter().
3. How do you manage packages using Node.js?
A variety of package installers and their associated configuration files can be used to manage the task. Utilize yarn and npm for the best part.
Both provide enhanced capabilities to manage specific configurations for environments which are accessible to virtually any of the JavaScript libraries.
We rely on package.json along with package-lock.json to update different versions of the libraries we have installed within a project so that the transfer of that application to a different system isn’t difficult.
4. What’s the reason Node.js is only one-threaded?
Node.js supports async processing by using only one thread. In contrast to the traditional thread-based architecture, better performance and scalability could be gained through the use of async processing on only one thread, under normal web load.
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5. Is a callback a function Node.js?
When a task is finished a callback function has been initiated. It prevents blocking and allows the execution of any other program during the time. Since Node.js is an Asynchronous platform, callbacks can be extremely important. The Node APIs have been specifically designed to work with callbacks.
6. In what sense do You define I/O?
Any process, program or device that carries data from or from one medium to the other is known as I/O.
Transfers are always an input to one medium and output into a different one. Physical devices networks, or even files within systems can all act as the media.
7. What’s the purpose of the function “.Exports”?
If you want to transfer all the relevant functions into one document, the module from Node.js can convert all the code that is connected into a single piece of code. A module can be exported by its purpose and can be incorporated into a new project using the appropriate keyword.
8. Which of the databases is utilized with Node.js more often?
The most well-known database that is used in conjunction with Node.js is MongoDB. It is a document-oriented cross-platform NoSQL database that has simple scalability as well as high availability and outstanding performance.
9. Which node.js command is used to import other libraries?
The “require” command allows you to import libraries from other sources. Utilizing “var http=require (“HTTP”)” as an example. By making use of”require” with the HTTP variable, it loads the HTTP library as well as the single object exported.
10. What exactly does a Node.js event loop perform?
The synchronous callbacks of Node.js are controlled by event loops. It is among the most essential elements in the environment as it is the basis for Node.js’s non-blocking input and output.
11. How can a basic Express.js application be developed?
A request object which contains attributes that represent the query body, text, parameters, HTTP headers, and more, is an HTTP request.
If the Express program receives an HTTP request it responds by sending the form of an HTTP object.
12. What exactly does Node.js”REPL” denote?
“Read Eval Print Loop,” or REPL is a symbol that represents an environment for computers. It’s similar to typing commands into a shell of Unix/Linux as well as a Windows console. The system will then produce an output as a result.
13. What are the main differences between synchronous and Asynchronous functions?
The development of large-scale Node.js apps requires the application of asynchronous functions that allow other programs to execute simultaneously with their code while the synchronous functions shut down until they’re completed.
14. In Node.js how do environment variables are handled?
The environment variables of Node.js are controlled via process.env. Keys and configurations for the environment that we can provide are stored in the.env file.
The syntax “process.env.VARIABLE_NAME” is used to access the variable within the application. To use it, you must run this command to install the dotenv application:npm install dotenv
15. Explain what is the Redis Module for Node.js.
A free Data Structure Storage System is known as Redis. It is a system that can be used in a variety of ways. It can serve as a messaging broker, database and cache.
Data structures such as string sets, hashes bitmaps, set streams, indexes, and strings can be all stored in it.
Redis is an excellent option for Node.js developers because it minimizes the size of the cache, which enhances the performance of applications. However, Redis integration with Node.js applications is quite easy.