What is Node.js: A Comprehensive Guide

Node.js is an extremely powerful JavaScript-based platform used to develop online chat applications, video streaming sites, single-page applications, and many other I/O-intensive web applications and web apps. Built on the JavaScript V8 Engine of Google Chrome, It is used by large, established companies and newly-minted startups alike (Netflix, Paypal, NASA, and Walmart, to name a few).

Node.js is open-source and completely free, used by thousands of developers around the world. It brings plenty of advantages to the table, making it a better choice than other server-side platforms like Java or PHP.

If you're new to Node.js or just getting up to speed on its core concepts, this article will give an introduction to the main fundamentals of this JavaScript-based platform. The following article covers the basics of this Node.js, why it's used, its different parts, the Node.js Express framework, use cases, and industry trends.

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What is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime environment and library for running web applications outside the client's browser. Ryan Dahl developed it in 2009, and its latest version, v13.8.0, was released on Jan. 30. Node.js is used for creating server-side web applications and is perfect for data-intensive applications since it uses an asynchronous, event-driven model.

Now that we know what Node.js is let's go ahead and take a look at why it is so prevalent in the field of web development.

Why Node.js?

Node.js has become the de facto tool for developing server-side and network applications. Here is why:

1. Node.js is really fast: Having been built on Google Chrome's V8 JavaScript engine, its library is extremely fast for code execution.
2. Node Package Manager (NPM): Node Package Manager has more than 50,000 bundles, so whatever functionality is required for an application can be easily imported from NPM.
3. Node.js uses asynchronous programming: All APIs of Node.js library are asynchronous (i.e., non-blocking), so a Node.js-based server does not wait for the API to return data. The server calls the API, and in the event that no data is returned, the server moves to the next API the Events module of Node.js helps the server get a response from the previous API call. This also helps with the speed of Node.js.
4. No buffering: Node.js dramatically reduces the processing time while uploading audio and video files. Node.js applications never buffer data and simply output the data in chunks.
5. Single-threaded: Node.js makes use of a single-threaded model with event looping. As a result, it can provide service to a much larger number of requests than traditional servers like Apache HTTP Server.
6. Highly scalable: Node.js server responds in a non-blocking way, making it highly scalable in contrast with traditional servers, which create limited threads to handle requests.

These reasons more than justify the popularity of the Node.js platform and why it is being adopted by a large number of organizations and businesses. Now, let's familiarize ourselves with the different parts of Node.js.

Parts of Node.js

Fig: Parts of Node.js

Now, let's go through each part of Node.js to get a better understanding of the server-side platform as a whole.

Modules

Modules are like JavaScript libraries that can be used in a Node.js application to include a set of functions. In order to include a module in a Node.js application, use the require() function with the parenthesis containing the name of the module.

Fig: Include a module in Node.js

Node.js has many modules that provide the basic functionality needed for a web application. Some of them are mentioned in this table:

Fig: Node.js modules table

Console

The console is a module that provides a method for debugging that is similar to the basic JavaScript console provided by internet browsers. It prints messages to stdout and stderr.

Fig: Node.js console

Cluster

Node.js is built-on on the concept of single-threaded programming. Cluster is a module that allows multi-threading by creating child processes that share the same server port and run simultaneously.

A cluster can be added to an application in the following way:

Fig: Add cluster in Node.js

Global

Global objects in Node.js are available in all modules. These objects are functions, modules, strings, etc. Some Node.js global objects are mentioned in the table below:

Fig: Global objects table

Error Handling

Node.js applications experience four types of errors.

Fig: Node.js errors

Errors in Node.js are handled through exceptions. For example, let's handle the error that would occur when we divide a number by zero. This error would crash the Node.js application, so we should handle this error to continue with the normal execution of the application.

Fig: Node.js error handling

Streaming

Streams are the objects that let you read data or write data continuously. There are four types of streams:

1. Readable: These are the types of streams from which data can be read
2. Writable: These are the types of streams to which data can be written
3. Duplex: These are both readable and writable streams
4. Transform: Streams that can manipulate the data while it is being read or written

Buffer

Buffer is a module that allows the handling of streams that contain only binary data. An empty buffer of length '10' can be created by this method:

Fig: Node.js buffer

Domain

The domain module intercepts errors that remain unhandled. Two methods are used for intercepting these errors:

1. Internal Binding: Error emitter executes its code inside the run method
2. External Binding: Error emitter is explicitly added to a domain via its add method

DNS

DNS module is used to connect to a DNS server and perform name resolution by using the following method:

Fig: DNS resolve

DNS module is also used for performing name resolution without a network communication by using the following method:

Fig: DNS lookup

Debugger

Node.js includes a debugging utility that can be accessed by a built-in debugging client. Node.js debugger is not feature-packed but supports the simple inspection of code. The debugger can be used in the terminal by using the 'inspect' keyword before the name of the JavaScript file. In order to inspect a file—myscript.js, for example—you can follow this method:

Fig: Node.js debugger

Now that we are familiar with the main parts of Node.js let's go ahead and learn about the Node.js Express framework.

Node.js Express Framework

Express is a flexible Node.js web application framework that provides a wide set of features to develop both web and mobile applications. It's a layer built on the top of the Node.js that helps manage a server and routes.

Now look at some of the core features of the Express framework:

• Used for designing single-page, multi-page, and hybrid web applications
• Allows developers to set up middlewares for responding to HTTP Requests
• Defines a routing table that is used to perform different actions based on the HTTP method and URL
• Allows dynamic rendering of HTML Pages based on passing arguments to templates

Now look at an example of a simple "Hello World" program developed using the Express framework to gain a better understanding of this framework.

Fig: Node.js Express framework, "Hello World."

• var express: Importing Express framework into our Node.js application
• app.get(): Callback function with parameters ‘request’ and ‘response’
• The request object: It represents the HTTP request and has properties for the request query string, parameters, body, HTTP headers, etc.
• The response object: It represents the HTTP response that an Express app sends when it gets an HTTP request.
• The application will listen to the defined port, which in this case is "8081," and variables "host" and "port" will contain the address and the port, respectively.
• console.log: This is to show the address and port in the command prompt or terminal.

Having learned about the Express framework, let's now move on to the use cases of Node.js.

Node.js Use Cases

Fig: Node.js use cases

Netflix

Fig: Netflix

Netflix, the world's leading online entertainment network with more than 167 million users, is one of many top companies trusting Node.js for their servers. The reasons why the company chose to use Node.js include:

• Application scalability
• Data-intensive application

Walmart

Fig: Walmart

Walmart is the world's largest company by revenue, with US$514.405 billion, according to the 2019 Fortune Global 500 list. Walmart chose to use Node.js because of the following attributes:

• Asynchronous I/O
• Efficient handling of concurrent requests

Uber

Fig: Uber

Uber is a U.S.-based, multinational ride-hailing company offering services that include peer-to-peer ridesharing, ride service hailing, and food delivery. The reasons why the company chose to use Node.js include:

• Asynchronous I/O
• Quick iterations
• Active open-source community

NASA

Fig: NASA

NASA, an independent agency of the United States Federal Government, is responsible for the civilian space program, as well as aerospace and aeronautics research. NASA chose to use Node.js for the following reasons:

• Reduced access times
• Ability to handle data-intensive tasks
• Capability to keep the server active 24/7

Paypal

Fig: Paypal

PayPal is a U.S.-based company operating a global online payment system that supports online money transfers, that is serving as an electronic alternative to traditional paper methods like checks and money orders. PayPal chose to use Node.js for the following reasons:

• Extremely fast build times
• Fewer lines of code
• Ability to handle large amounts of data

Medium

Fig: Medium

Medium is a popular online publishing platform developed by Evan Williams and launched in August 2012. The reasons why the company chose to use Node.js include the following:

• Data-driven applications
• Ability to run A/B tests
• Simple server maintenance

Industry Trends

Node.js developers are in demand around the world due to the wide adoption of this JavaScript library. It is among the top 10 most in-demand jobs, according to Forbes.

Fig: Node.js Source Report

• The total number of Node.js downloads increased by 40% in 2018, according to Node Source.
• The use of Node.js in production has increased dramatically since its release in 2010.

With adopters such as Netflix, Paypal, and other tech companies, Node.js has seen an exponential increase in its use in web development.

The popularity of Node.js is also due to the fact that it's built on JavaScript. Since JavaScript is the most popular language, as evident from the survey conducted by Stack Overflow in 2019, many developers can start working on the Node.js library without too steep of a learning curve.

Source: Stack Overflow Report 2019

• Node.js developers are being offered better salary options than other web technology developers.

The average salary of a Node.js developer in India is ₹6,13,000 per year!

The average salary of a Node.js developer in the United States is $104,964 per year!

Get Ahead of the Curve and Master Node.js Today

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