“Node.js Interview Questions and Answers: Comprehensive Guide for Succes
Introduction
“Any application that can be developed in JavaScript will be written in JavaScript at some point.” Jeff Atwood’s
This was stated in 2007, and it continues to hold true today. Consider any technical term, and there may be a JavaScript library built around it. As a result, if it’s so popular and in demand, this could be a terrific programming language to learn. However, that is not the only talent necessary, as you must use it to solve actual problems. One of these issues is the creation of scalable products.
Gen Z backend
After jQuery animation development migrated to a single page application for better control of ui/ux, frontend frameworks such as angular js and angular came into play. Following that, JavaScript was made available for porting into virtually any modern system and running as a standalone programme, i.e. Node.js. It is widely regarded as a backend framework and ranks first in the StackOverflow survey for the second year in a row in 2020.
The following is a list of the most often asked Node.js interview questions and answers.
- What is Node.js?
Node.js is a cross-platform open-source JavaScript runtime environment that allows JavaScript code to be executed outside of a web browser. It enables developers to create server-side and networking apps by running JavaScript on the server. Because Node.js has an event-driven, non-blocking I/O mechanism, it is lightweight and efficient for data-intensive real-time applications that run across dispersed devices. It is extensively used to create back-end services such as APIs and microservices, and it is frequently combined with other technologies such as MongoDB and AngularJS to create full-stack JavaScript applications.
- Is Node.js free to use?
Yes, Node.js is free to use and is open-source software released under the MIT License.
- Is Node a single threaded application?
No, Node.js is not a single-threaded programming language. Node.js executes JavaScript code in a single-threaded event loop and performs non-blocking, asynchronous I/O operations in a separate pool of threads. This enables Node.js to handle several concurrent connections without the need for multiple processes or threads, which improves performance and scalability significantly.
- What is the purpose of Node.js?
Node.js’s objective is to provide a JavaScript runtime for developing server-side and networking applications. It enables developers to construct dynamic web pages, APIs, and other server-side features using JavaScript on the server. Node.js is lightweight and efficient because it employs an event-driven, non-blocking I/O paradigm. It also has a huge and active community that offers a variety of modules and tools to assist developers in building various types of apps.
- What are the advantages of Node.js?
Among the benefits of utilising Node.js are:
It enables the usage of JavaScript on both the frontend and the backend, enabling for full-stack JavaScript development. It employs an event-driven, non-blocking I/O architecture, making it well-suited for real-time applications and high-traffic settings.
It has a strong and active community that contributes a plethora of packages and modules to expand its capability.
It is lightweight and efficient since it use V8, Google’s JavaScript engine built for use in their Chrome browser.
- Explain Node.js web application architecture?
Node.js is a JavaScript runtime that enables developers to execute JavaScript on the server. A typical Node.js web application has the following architecture:
A Node.js script handles the HTTP request sent by the client to the server.
To handle HTTP requests and routes, the Node.js script employs modules such as Express or Koa.
To get or store data, the script communicates with a database, such as MongoDB or MySQL.
The script generates and sends an HTML or JSON response to the client.
When the response is received, the client renders the HTML or processes the JSON data.
Node.js serves as both the web server and the application server in this design, managing both the front-end and back-end of the application. Because the same language (JavaScript) can be used on both the client and server sides, web applications may be developed efficiently and quickly.
- What do you understand by the term I/O?
I/O refers to input/output operations in Node.js, such as reading or writing data to a file or connecting to a network. Node.js employs an event-driven, non-blocking I/O approach that allows it to efficiently handle a large number of concurrent connections. This means that, rather of waiting for an I/O operation to complete before proceeding to the next task, Node.js may handle many I/O operations concurrently via callbacks or events. This enables for more efficient use of system resources and can significantly enhance Node.js application performance.
- How many types of API functions are available in Node.js?
Node.js provides numerous sorts of API functions, including:
File System (fs)
HTTP
Cryptography (crypto)
Streams
Events
Path
Assert
Timers
Util
DNS
OS
Process
Child Process
Cluster
Zlib
These are just a few instances of the many built-in modules in Node.js that provide diverse functionalities. There are also numerous third-party modules available that can be installed using npm (Node Package Manager) to extend the capabilities of a Node.js application.
- What do you understand by the first class function in JavaScript?
In JavaScript, a first-class function indicates that functions are treated as first-class citizens, exactly like any other data type (e.g. numbers, strings, etc.). They can thus be assigned to variables, supplied as parameters to other functions, and returned as values from functions. This is widely utilised in Node.js in the form of callbacks, which are functions that are supplied as arguments to other functions and performed when certain events occur.
- What is the difference between JavaScript and Node.js?
JavaScript is a computer language that is often used on websites to create interactivity and other dynamic features. Node.js is a JavaScript engine that enables developers to run JavaScript on the server side, rather than within a web browser. In other words, JavaScript is a programming language, whereas Node.js is a platform that enables JavaScript to execute on a server. Node.js also has a large collection of modules that help to ease server-side programming and enable for easy integration with other technologies.
- Explain the working of Node.js?
Node.js is a JavaScript runtime based on the V8 JavaScript engine in Chrome. It enables developers to build quick and scalable network apps by running JavaScript on the server.
When you run a Node.js app, the V8 engine turns the JavaScript code into machine code, which is then executed by the computer’s processor. The Node.js Runtime Environment is a built-in library that provides several modules for standard server-side functions such as file system access, network connection, and more.
Node.js has an event-driven, non-blocking I/O approach, making it ideal for developing real-time, data-intensive applications. Node.js’ event loop is single-threaded, which means it can handle multiple concurrent connections without requiring multiple threads or processes.
As a result, Node.js is well-suited for developing highly concurrent and high-performance network applications such as real-time chat apps, online gaming, and streaming services.
- How can you manage the packages in your Node.js project?
In a Node.js project, there are multiple approaches to handle packages:
npm (Node Package Manager): This is Node.js’s default package manager, and it comes pre-installed. You can use npm in your project to instal, update, and remove packages.
Yarn is a popular Node.js package manager. It’s faster and more secure than npm, and it offers a feature called “yarn workspaces” that lets you manage many packages in a single repository.
pnpm: This is another package manager that is similar to yarn, but it is faster and takes up less space.
lerna: This is a utility for managing various packages in a monorepo. It works great when combined with npm or yarn.
Although all of these package managers can instal packages from the npm registry, yarn and pnpm have their own registries.
To interact with the packages in your project, you can use the command line interface (CLI) of the package manager you chose.
- Why is Node.js Single-threaded?
To handle asynchronous I/O operations, Node.js employs a single-threaded event loop. This method enables it to handle a huge number of concurrent connections while consuming little memory. Furthermore, Node.js’ JavaScript runtime is built on the V8 JavaScript engine, which is also single-threaded and incredibly efficient. The single-threaded event loop also makes it simple to reason about and debug your program’s flow.
- What do you understand by callback hell in Node.js?
Callback hell is a condition that can arise when nested callbacks are used in JavaScript, particularly in Node.js. When numerous asynchronous activities must be completed in a precise order, the code might become deeply nested and difficult to read and understand. This is commonly referred to as “callback hell” since it can cause the code to feel chaotic. To avoid callback hell, developers can utilise techniques like Promises or async/await, which make writing and reasoning about asynchronous programming easier.
- How is Node.js better than other most popular frameworks?
Node.js is a JavaScript runtime that enables developers to execute JavaScript on the server. It is based on the V8 JavaScript engine, which is the same engine used by Google Chrome to run JavaScript. Among the benefits of Node.js over other popular frameworks are:
It employs JavaScript, a widely used and well-known programming language that is simple for developers to learn and apply.
It has a large and active community, which means there is plenty of help and tools for creators.
Because of its asynchronous, non-blocking I/O style, it enables quick and efficient development.
It’s small and efficient, making it ideal for real-time applications and high-traffic websites.
It works with a variety of operating systems, including Windows, Linux, and macOS.
Overall, Node.js is a robust and adaptable framework suitable for a wide range of applications. It is ideal for real-time, high-traffic applications, as well as for developers who are already comfortable with JavaScript.
- In which types of applications is Node.js most frequently used?
Node.js is most commonly used in the development of online applications, real-time applications (such as chat or gaming), and the creation of back-end services and APIs. It is also utilised in Internet of Things (IoT) applications, as well as in the development of command-line tools and utilities.
- What are some commonly used timing features of Node.js?
Node.js timing characteristics that are often used include the following:
setTimeout: You can use this function to perform a callback function after a certain period of time has passed.
setInterval: This function allows you to run a callback function at a predefined interval.
process.nextTick: This function lets you arrange a callback function to be executed on the event loop’s next tick.
Date: It allows you to work with dates and timings.
setImmediate: This function allows you to perform a callback function as soon as the current event loop cycle has finished.
performance.now() returns the number of milliseconds since the navigation began.
requestAnimationFrame(): This function lets you to run a function right before the browser repaints.
- What do you understand by the term fork in Node.js?
The term “fork” in Node.js refers to the act of generating a new child process. This child process is a carbon clone of the parent process, but it runs autonomously and has its own memory space. Inter-Process Communication (IPC) channels allow the child process to communicate with the parent process. The fork() function in Node.js’s child process module can be used to create a new child process.
- Which is the best tool we can use to assure consistent code style in Node.js?
ESLint is a popular tool for verifying consistency in Node.js code style. It lets you specify a set of rules for your project and automatically checks your code for compliance. ESLint is also highly adjustable and simple to integrate into your development workflow, making it an ideal solution for enforcing code style norms in Node.js projects.
- What is the main difference between front-end and back-end development?
Front-end development is largely concerned with the client-side of an application, and it entails creating the user interface and user experience. Languages like as HTML, CSS, and JavaScript are commonly used. Back-end development, on the other hand, is focused on an application’s server-side and involves the design of the application’s logic and functionality. JavaScript is used in both front-end and back-end programming in Node.js. The primary distinction between front-end and back-end development in Node.js is the execution environment, as front-end code runs in a web browser while back-end code runs on a server.
- Give an example to demonstrate how can we use async await in Node.js?
Here’s an example of a Node.js script that uses the async and await keywords to make an HTTP request and print the response:
const https = require(‘https’);
async function makeRequest() {
const response = await https.get(‘https://jsonplaceholder.typicode.com/posts/1’);
const data = await response.json();
console.log(data);
}
makeRequest();
In this case, makeRequest is an async function that uses the https module to send an HTTP GET request to a JSON placeholder API. Before the resulting data is logged to the console, the await keyword is used to wait for the response to the call, as well as the response’s json() method.
- What are the modules in Node.js? Which are the different modules used in Node.js?
Node.js includes an in-built module system, which means it comes with a collection of pre-built modules that can be used to accomplish a variety of functions. The following are some of the most often used built-in modules in Node.js:
http: used in the development of HTTP servers and clients
fs: This command is used to interact with the file system.
path: utilised when dealing with files and directories paths
util: utilised for utility purposes
events: used in event-driven programming streams: utilised when working with data streams
crypto: a term used in cryptographic functions.
zlib: a compression and decompression library.
Furthermore, Node.js allows you to use and construct your own modules for usage in your code via the need() function.
Third-party modules, which are produced and maintained by the community, can also be used and are simply installed using a package manager such as npm. Among the most popular third-party modules are:
Express is a Node.js web framework.
Mongoose is an object modelling tool for MongoDB.
Socket.io is a library for real-time communication.
React is a JavaScript library used to create user interfaces.
Lodash is a utility package that allows you to work with arrays, numbers, and objects.
Passport is a Node.js authentication middleware.
Webpack is a JavaScript application module bundler.
- What are buffers in Node.js?
A buffer is a piece of memory in Node.js that contains binary data, analogous to an array of integers. Buffers are used in Node.js to handle binary data, such as reading from a stream or writing to a file. They are more efficient than JavaScript’s built-in string or array data types for manipulating and processing binary data. Buffers can also be used for cryptographic operations and other low-level I/O.
- What is error-first callback?
An “error-first callback” is a Node.js design convention for callback functions in which the first input supplied to the callback is an error object. If the function encountered an error, the error object will contain information about the error; otherwise, it will be null or undefined. This makes error management and propagation easier across the application.
As an example:
function someAsyncFunction(callback) {
doSomething(function(err, result) {
if (err) {
return callback(err);
}
callback(null, result);
});
}
The callback function accepts two parameters in this case. If an error occurs during the execution of doSomething, the first parameter is an error object. If there are no errors, it is returned as null. The second argument is the operation’s outcome.
- What is an asynchronous API?
In Node.js, an asynchronous API is a form of API that enables for non-blocking, event-driven I/O operations. This means that the API can continue to execute code while waiting for a response from an external resource, such as a database or a web service, without interrupting the program’s execution. This enables for more efficient use of system resources and can increase programme performance. In Node.js, asynchronous programming is accomplished through the use of the async and await keywords, as well as callbacks and promises.
- How can you avoid callbacks?
In Node.js, you can avoid using callbacks by utilising async/await, which allows you to write asynchronous code that appears synchronous. Instead of passing a callback function, the await keyword can be used to wait for a promise to resolve before proceeding to the next line of code. Another option is to utilise a library that provides utility functions for working with asynchronous code, such as async or promise.
Instead of utilising a callback, for example:
fs.readFile(‘file.txt’, function(err, data) {
if (err) {
// handle error
}
// use the data
});
You can employ async/await:
async function readFile() {
try {
const data = await fs.promises.readFile(‘file.txt’);
// use the data
} catch (err) {
// handle error
}
}
Another technique to avoid callbacks is to use libraries that give an abstraction over callbacks and a simpler API, such as fs-extra, which has the same API as fs but with some additional methods such as fs.copy, which is a promise-based alternative to fs.copyFile.
const fs = require(“fs-extra”);
async function moveFile(){
try{
await fs.move(“oldFile.txt”, “newFile.txt”);
}catch(err){
console.error(err);
}
}
It is crucial to remember that, while callbacks can be avoided, the underlying code may still use them internally.
- Does Node.js provide Debugger?
Yes, Node.js includes a built-in debugger for debugging JavaScript code running on the Node.js runtime. The debugger can be started from the command line with the node debug command, or using a tool like the Node.js Debugger module or a third-party debugging tool like VS Code or WebStorm. Set breakpoints, step through code, analyse variables, and do other debugging activities with the debugger.
- What is a control flow function?
A control flow function in Node.js is a function that helps control the flow of asynchronous code execution. These functions enable developers to perform many asynchronous activities in a certain order or in parallel, as well as handle errors and completion of the operations. Node.js control flow functions include async.series, async.parallel, and async.waterfall.
- How “Control Flow” controls the functions calls?
Control flow in Node.js refers to the order in which code is executed. The structure of the code, such as conditional statements (e.g. if-else) and loops (e.g. for, while), as well as the sequence in which functions are called, define this.
For example, if a function is called within an if statement, it will be performed only if the if statement’s condition is true. Similarly, a function called within a loop will be executed several times depending on the loop’s circumstances.
Furthermore, Node.js employs asynchronous programming, which allows several processes to be completed concurrently. This means that even if a function is called, the programme will keep running and execute other code. This is accomplished by use callback functions and Promises.
Overall, in Node.js, control flow dictates the order in which code is performed, and it is determined by the structure of the code as well as the order in which functions are called utilising conditions, loops, and async programming.
- Is it possible to access DOM in Node?
Node.js does not have direct access to the DOM (Document Object Model), as it is a JavaScript runtime used for server-side programming and does not have access to a web browser’s DOM. There are, however, modules in Node.js that can replicate a DOM environment, allowing you to run code that would normally interact with the DOM in a browser environment.
- What types of tasks can be done asynchronously using the event loop?
Asynchronous jobs in Node.js that can be completed via the event loop include:
I/O operations such as reading and writing to files and databases are examples of I/O operations.
Making HTTP requests, for example, is an example of network communication.
Performing time-consuming tasks, such as image processing or encryption
Working with the file system
gaining access to system resources such as CPU and memory
Timers and future job scheduling
User input or messages from a message queue are examples of event-based jobs.
- What is REPL in Node.js?
REPL is an abbreviation for “Read-Eval-Print-Loop”. REPL is a command-line interface in Node.js that allows users to interact with the runtime by inputting JavaScript code and viewing the results. It can be used to test and debug Node.js apps, as well as to play around with JavaScript code in general. The REPL prompts the user to enter JavaScript code, which the Node.js runtime will execute and print the result of. The REPL also includes a number of commands for controlling the environment, such as changing variable values or viewing a list of declared variables.
- Explain the tasks of terms used in Node REPL.
Node REPL (Read-Eval-Print Loop) is a command-line interface for Node.js that allows you to run JavaScript code. The following terms have tasks in Node REPL:
Read: Node REPL reads the user’s input.
Eval: The input is evaluated as JavaScript code by the Node REPL.
Print: Node REPL outputs the evaluation result to the console.
Node REPL then loops back to the read stage, awaiting the user’s next input.
Node REPL also has a number of command-line parameters and key bindings to improve the user experience. for instance:
In addition, Node REPL includes a number of command-line options and key bindings to improve the user experience. for example:
To access the previous command, use the up and down arrow keys.
To see all commands, use the help command.
To exit a multi-line expression, use the break command.
To quit a multi-line expression, use the clear command.
To save the current session to a file, use the save command.
To load a file into the current session, use the load command.
To begin editing in the default editor, use the editor command.
- Is it possible to evaluate simple expressions using Node REPL?
Yes, you can use the Node.js REPL to evaluate simple expressions (Read-Eval-Print Loop). The REPL is a command-line interface that allows you to run JavaScript code and see the results immediately. Expressions can be entered into the REPL to get their values back.
- What is the use of the underscore variable in REPL?
The underscore (_) variable is used to store the result of the last evaluated expression in a Node.js REPL (Read-Eval-Print Loop). This allows you to simply refer to the result of a previous command without re-evaluating the full phrase. For example, if you ran the expression 2 + 2 in the REPL, the result would be saved in the underscore variable, and you could access it later by typing . This can be handy for debugging or chaining together several tasks.
- Does Node.js supports cryptography?
Yes, Node.js supports cryptography through its built-in crypto module, which includes a suite of cryptographic methods for hashing, signing, and encryption. This module is included with Node.js by default and may be imported and used in your application without the need for any extra dependencies. Furthermore, there are third-party libraries for Node.js that can be utilised for advanced cryptography functions.
- What is npm? What is the main functionality of npm?
npm (short for Node Package Manager) is the default package manager for the JavaScript programming language and the JavaScript runtime environment Node.js. With over 1.3 million packages, it is the world’s largest software registry. The primary function of npm is to assist in the management and sharing of packages (libraries, frameworks, tools, and so on) used in a Node.js project. It enables developers to effortlessly instal, update, and manage project dependencies, as well as share their own packages with others. npm also provides a command-line interface for developers to connect with the registry and execute operations like installing packages, running scripts, and managing dependencies.
- What tools can be used to assure a consistent style in Node.js?
There are numerous tools available to maintain consistency in Node.js code:
ESLint: a well-known JavaScript linter that may be set to enforce a specific code style.
Prettier: a code formatter that can automatically format code to conform to a particular style.
JSHint is yet another JavaScript linter that may be set to enforce a specific code style.
JSLint is yet another JavaScript linter that may be set to enforce a specific code style.
StyleLint is a CSS, SCSS, and other style language linter that may be used to ensure consistency in stylesheets.
Husky is a programme that allows you to set git hooks that may be used to run linting and formatting tools automatically before committing code changes.
It’s also worth noting that many major code editors and IDEs include plugins for the aforementioned tools that can assist you enforce a consistent style as you write code on the fly.
- What is the difference between operational and programmer errors?
Operational errors, sometimes known as runtime errors, are problems that occur during a program’s normal execution, such as a missing file or a failed network connection. These errors are usually unanticipated and outside of the program’s control.
Programmer mistakes, also known as logic errors, are errors that arise as a result of a mistake in the program’s logic or code, such as assigning the incorrect value to a variable or calling a function with the incorrect inputs. These errors are usually the consequence of a programme flaw and can be rectified by the developer.
Operational mistakes in Node.js are often represented by instances of the built-in Error class, although programmer errors may simply be thrown strings or other data types. In order to avoid the application from crashing, operational problems must be caught and treated effectively, whereas programming errors must be rectified and managed by the developer before release.
- What is the difference between the global installation of dependencies and local installation of dependencies?
A global installation of dependencies in Node.js means that the modules are installed globally on your system and are accessible to any projects running on that machine. A local installation of dependencies, on the other hand, means that the modules are installed in the directory of a single project and are only accessible to that project. The main distinction is that global modules can be accessible by any project on a machine, whereas local modules can only be accessed by the project where they are placed.
- What is the use of a buffer class in Node.js?
In Node.js, raw binary data is handled using a buffer class. It is comparable to an integer array, except it corresponds to a raw memory allocation outside of the V8 heap. Buffers can be used to work with binary data, such as reading from a stream, or to create network protocols. They can be used to perform a range of activities, including image processing, reading and writing to streams, and data decoding and encoding. Buffers are also more efficient than JavaScript strings for manipulating and working with binary data.
- What is the role of assert in Node.js?
Assert is a built-in module in Node.js that allows you to determine whether a given expression is true or false. If the expression is false, an AssertionError with an optional error message is thrown. It is frequently used to test for a program’s predicted output and can be used as a simple technique to confirm that the programme is running as planned.
- What are the streams in Node.js?
Streams are a non-blocking, asynchronous manner of reading and writing data in Node.js. They are read-write objects that allow you to interact with massive volumes of data without having to load the entire dataset into memory. Node.js streams are classified into four types: readable, writable, duplex, and transform.
A readable stream is one that can be read data from.
A Writable stream is one that can be written to.
A Duplex stream is one that can be read and written to.
A Duplex Transform stream can change or transform the data as it is read and written.
- What is event-driven programming in Node.js?
The flow of a programme is dictated by events such as user interactions, sensor outputs, or messages from other programmes or threads in event-driven programming. Event-driven programming in Node.js is accomplished through the usage of the event-loop, which allows the programme to listen for and respond to events as they occur, rather than processing a linear sequence of instructions. This enables Node.js to easily manage several concurrent events and actions, making it well-suited for developing high-performance, scalable network applications.
- What is the difference between events and callbacks in Node.js?
An event in Node.js is an indication indicating something has occurred in the application. A callback is a function that is run in response to an event. Any callback functions that are listening for an event will be invoked when it occurs. The EventEmitter class in Node.js is commonly used to manage events, allowing developers to build and listen for custom events. Callbacks are used by developers to define what should happen when an event happens.
- What is the Punycode in Node.js?
Punycode is a method of representing Unicode characters with the limited ASCII character set permitted by the Domain Name System (DNS). It is most commonly used for Internationalized Domain Names (IDNs) to encode non-ASCII characters in a format compatible with the normal ASCII-based domain name system. The punycode module in Node.js provides a means to convert between Unicode strings and Punycode strings, allowing Node.js applications to handle IDNs.
- What does Node.js TTY module contains?
The Node.js TTY module includes capabilities for working with terminal input and output. This provides methods for changing the mode of the terminal (such as raw mode, in which all input is transmitted through to the process) and determining the size of the terminal window. The module also offers ReadStream and WriteStream classes, which can be used to read from and write to the terminal, respectively.
- What are the key differences between Angular and Node.js?
Angular is a JavaScript framework for developing web apps, whereas Node.js is a JavaScript runtime for server-side JavaScript execution. Angular is primarily used for client-side application development, whereas Node.js is primarily utilised for server-side application development. Another distinction between the two is that Angular is a framework, but Node.js is a runtime environment. Angular has several built-in features for building web apps, such as two-way data binding, dependency injection, and a strong template system, whereas Node.js is primarily concerned with providing a means to run JavaScript on the server side and communicate with the file system and network.
- What are the main differences between operational and programmer errors?
When something unexpected happens during the execution of a programme, such as a network failure or a missing file, operational errors, also known as runtime errors, occur. These problems are frequently caused by external causes that are outside the programmer’s control.
Programmer errors also referred to as logic errors, arise when the code is erroneous, such as a typo or an off-by-one error. These faults are the result of the programmer’s actions and can be corrected by altering the code.
Operational problems in Node.js are commonly represented by instances of the built-in Error class, although programmer errors can take numerous forms, such as syntax errors or logical faults in the code. To manage operational mistakes, try-catch blocks are commonly used, although programmer errors are normally addressed during the development phase through testing and debugging.
- What do you understand by an EventEmitter in Node.js?
In Node.js, an EventEmitter is a class that allows objects to emit events and register listeners for those events. It is frequently used to facilitate asynchronous communication between different portions of an application, letting them send and receive messages. Node.js includes the EventEmitter class, which can be utilized by extending it or making an instance of it. The EventEmitter class includes methods for registering and removing event listeners, as well as emitting events, such as on(), emit(), and removeListener().
- What is the difference between readFile and createReadStream in Node.js?
fs.readFile is a method in Node.js’s fs (file system) module that reads the contents of a file. It accepts a file path as an argument and returns the file’s contents as a buffer or string. Because it reads the whole contents of a file into memory before returning the data, it may not be appropriate for huge files.
fs.createReadStream is another function in the fs module for reading the contents of a file. It accepts the file path as an input as well. Instead of reading the complete contents of the file into memory all at once, it creates a stream of data that can be read in stages. This increases efficiency for huge files and enables more diverse use cases, such as reading data from a stream while it is still being written to.
To summarise, fs.readFile reads a file’s whole contents into memory and returns it all at once, whereas fs.createReadStream reads a file’s contents in chunks and returns them as a stream.
- What is the concept of Punycode in Node.js?
Punycode is a method of representing Unicode characters with the limited ASCII character set permitted by the Domain Name System (DNS). It is used to convert non-ASCII internationalised domain names (IDNs) to a format that can be used with conventional DNS. The punycode module in Node.js allows you to transform strings containing non-ASCII characters to Punycode and vice versa. This enables Node.js applications to work with IDNs and other Unicode strings in a DNS-compatible manner.
- How can you enhance the Node.js performance through clustering?
Clustering in Node.js allows many instances of the Node.js process to operate concurrently, which can dramatically improve speed by utilising multiple CPU cores. The cluster module, which is built into Node.js, is a popular library for implementing clustering. To use it, establish a master process that forks a set number of worker processes and then distributes incoming requests among them. This enables load balancing and failover capabilities, which improves the application’s overall performance and stability. Another option is to utilise a cluster manager such as PM2, which enables automatic load balancing, process monitoring, and automatic failover.
- What is a thread pool in Node.js? Which library handles it?
In Node.js, a thread pool is a collection of worker threads that are used to conduct non-blocking, asynchronous I/O operations. The thread pool is used to prevent the generation of new threads for each I/O activity, which can consume a lot of resources. Instead, the pool’s worker threads are reused to conduct many I/O operations, enhancing performance and lowering the danger of thread exhaustion.
Thread pooling is handled by the Node.js built-in library ‘worker threads’. It enables the creation of multiple worker threads for running JavaScript code concurrently with the main thread. It also has a fixed-size ThreadPool that is utilised for operations such as file I/O, encryption, zlib, and other C++ addons.
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