Node JS Tutorial

What is Node.js?

Many new developers mistake Nodejs for a programming language like C++ or python. But it is not a programming language. However, it is written with the help of C++, C, and Javascript. Node.js is open-source software (publicly accessible), cross-platform (different operating environment) Javascript runtime environment that runs on chrome’s V8 engine internally.

As a result, Node.js allows developers to build server-side applications in Javascript; developers can execute Javascript code outside the browser. Node.js package ecosystem that is NPM (node package manager) is the largest ecosystem of the open source libraries in the world.

Before Node, developers were only able to run Javascript inside browsers. Hence to connect your program to a database or to edit data, you need support from other server-side programming languages like PHP, Python, or Ruby. In 2009, Ryan Dahl embedded chrome’s V8 engine (the most powerful and fastest) inside a C++ program and called it Node.

From a developer’s perspective, Node.js looks asynchronous, event-driven, and single-threaded, although, under the hood, Libuv handles threading and the Event loop. The V8 engines directly convert Javascript code to faster machine code which the interpreter can run more efficiently.

Audience

The goal of this tutorial is to teach software developers the fundamentals of Node.js and its architectural ideas. With appropriate examples, this course will provide you with a thorough grasp of all the necessary components of Node.js.

Pre-requisite

Now that you've learned more about Node.js, you should have a clearer idea of how it might enhance your skill set. Let us now look at the prerequisites for studying Node.js.

• JavaScript - We must have a solid grasp of both the fundamental and more complex principles of JavaScript because the Node.js environment was designed for creating javascript code. Knowledge of expressions, loops, data structures, callbacks, functions, objects, this keyword, event handlers, and other related javascript basics is required. Before learning Node.js, it is advised that you review your JavaScript principles.
• Asynchronous code - You must be well familiar with asynchronous programming and how it functions before digging into Node.js. The ability to perform numerous activities simultaneously without interfering with the main thread execution is known as asynchronous code or architecture. Callbacks in JavaScript make use of this asynchronous model. The majority of the functions in Node.js are asynchronous in nature.
• CLI - Command Line Interface, or CLI for short, is a text-based user interface that allows you to enter commands to direct your computer to carry out certain actions. Once you're familiar with the Command Line Interface, you'll be able to smoothly run nvm, and npm, and execute your Node.js applications.
• NPM - A very effective solution for managing the server-side dependencies of any Node.js project is the Node Package Manager, or NPM. NPM makes it simple to install, update, and, if necessary, remove different JavaScript libraries and packages. The most well-liked package manager among developers is Yarn, which was created by Facebook engineers, and is one of the many that is functional with Node.js in addition to NPM.
• HTTP - When you need to obtain data from a data source or submit data to a server, you must make an API request to that server over HTTP. A fundamental understanding of HTTP methods and HTTP requests like as GET, POST, DELETE, PUT, PATCH and so on would be useful when working on a web project.
• Understanding of ES6+ - Currently, the standard scripting language for JavaScript is ECMAScript 2015 or ES6. The second significant update to JavaScript is called ES6, and it includes significant additions like the let and const keywords, for loops, default arguments, classes, arrow functions and many more. As a result, it is recommended that you become acquainted with all of these features.

Why use Node.js?

The various key features of Node.js are as follows :

1. Simplicity - Javascript is one of the programming community's most liked and widely used languages. It has quite a simple syntax; hence one can easily adapt it. It also reduces the time to write codes. Node.js has an easy learning curve, as anyone who knows the concepts of server-side programming (Javascript) can learn it in no time. Also, developers can use a single language to develop entire full-stack applications (frontend and backend).
2. Single Threaded but Highly Scalable – Node.js is single-threaded. Some requests may take some time to process, but this does not block the execution of other processes. Thus Node.js is highly scalable. Node.js can provide service to a large number of requests using a single thread only.
3. Open Source - Node.js has the support of a large community of developers that have created numerous open-source modules for anyone to use.
4. Cross-platform Development - With Node.js, one does not need to spend time writing separate code for windows, Linux, and Mac. We can use the same code for a mobile application and a desktop version.
5. Real-Time Applications - Node.js offers high performance in Real Time applications due to its ability to multitask. The speed of I/O operations is enhanced by the non-blocking event loop.
6. There is a Vibrant and active community for the Node.js framework – Node.js is open source, and as it is widely used, a large community of highly skilled developers are supporting it.
7. Single Threaded but Highly Scalable – Node.js is single-threaded. Some requests may take some time to process, but this does not block the execution of other processes. Thus Node.js is highly scalable. Node.js can provide service to a large number of requests using a single thread only.
8. Concurrent request handling – As all APIs of Node.js are asynchronous hence any request for I/O is handled in the background, and the execution of other requests is not stopped. This makes execution faster.
9. Quick in Code execution – Node.js uses the Chrome’s V8 JavaScript Runtime engine. Node.js has a wrapper around the javascript engine that makes the processing faster.
10. Caching - Node.js provides caching of single modules. Requests get cached in application memory. This provides faster loading.

Who uses Node.js?

While Node.js is relatively young, it is far from innovative. For a good reason, Fortune 500 organisations prefer Node.js to alternative frameworks. Let't talk about few of them.

• LinkedIn is a professional social networking site. It is best suited for persons who want to advance in their careers. In late 2011, LinkedIn transitioned from Ruby on Rails to Node.js. This was primarily due to Linkedin engineers' need to optimise their mobile app, where everything is now written fully in Node.js and HTML5 and they were able to drastically minimise the server's resource requirements.
• Netflix is a television and film streaming service with millions of customers worldwide and is probably one of the most popular Node.js users.  The modularity of the framework, according to the Netflix team, prompted them to utilise Node.js.
• Uber is a taxi-like service for customers who need to go there quickly but are put off by the exorbitant prices of a yellow cab. Uber employees are regular folks who must go through background checks. Uber was one of the first to embrace Node.js to its maximum potential, creating the majority of the Uber platform on Node.js. Uber picked Node.js for three primary reasons: it processes information quickly, it is simple to check for errors, and it allows for ongoing development because of the open-source community.
• Trello is a collaborative online application for organisations that uses virtual boards to coordinate projects and ideas. The user of a typical Trello dashboard can learn what is being worked on, who is working on it, and what stage of development the project is in. Trello's server-side code is written in Node.js. Trello and its application users need real-time updates, and Node.js can handle a large number of open connections simultaneously.
• PayPal is one of the most famous online payment platform for conducting secure electronic payments. Node.js is used by PayPal to build user-facing content. The PayPal software team enjoys the fact that Node.js enables developers to create both client-side and'server-side' JavaScript applications.
• Walmart is a prominent American retailer with supermarkets and retail stores all around the world. Walmart is one of the businesses that utilise Node.js, and it employs the framework to build its user interfaces (UIs) as well as application programming interfaces (APIs) for the company's many apps. Developers can link numerous apps or services together using orchestration layers. In essence, Walmart app users can access numerous unique tasks through a single platform.
• GoDaddy is a website hosting company that also registers domain names over the internet. Node.js is used to power their back-end infrastructure. Senior Software Developer Stephen Commisso believes this is due to the company's ability to create high-quality apps and provide new features swiftly. Furthermore, Node.js is useful for testing, NPM resources, and REST. REST sets standards between computer systems and web services, which is a useful feature for GoDaddy developers.
• The National Aeronautics and Space Administration, or NASA as it is commonly known, is an organisation supported by the American government that is in charge of conducting  space-related exploration and research. Node.js has a feature called microservices that allows programmers to build applications by exposing the software as a group of discrete services rather than as a single autonomous entity. NASA was able to migrate its enterprise to the cloud by utilising this functionality.

When to Use Node.js?

Node.js is ideally suited for use in applications like :

• Game servers - If you require fast and high-performance servers that can handle a lot of requests simultaneously, then this is the framework for you.
• Excellent for a collaborative atmosphere - This is beneficial in environments where documents are managed. Multiple persons will submit their documents and make frequent modifications by checking out and checking in documents in a document management environment. Node.js is, therefore, suitable for these setups since it allows it has the event loop, which will be triggered whenever documents are modified in the environment.
• Real-time web apps / chat apps - The event-driven architecture of node.js is appropriate for real-time applications, especially chat applications and games.
• Streaming servers - Using Node for multimedia streaming servers, where clients are requesting to download various multimedia items from the server, is another case in which Node js excels.

How Long Does It Take to Learn Node.js?

To master Node JS and be able to create a useful full-stack application typically takes around three months. You can master the fundamentals in a few weeks if you have experience with other types of programming.

This is due to a large number of moving elements that go into creating functional software, such as a social network or a chat application. It will take you a similar amount of time to progress from novice to expert in web application deployment by following a video course.

Of course, the real-time it takes to learn something relies entirely on your hard work, determination, how much effort you can put in to learn the particular topic, and what kind of abilities you already have that you can leverage.

There is a great deal to discuss on the topic of node js.  You can study something for long periods of time and feel as though you still don't know enough about it. This is why you must be strategic in your learning objectives. Instead of understanding all there is to know about Node JS, focus on a tiny subset and excel at it.

About this Node.js Tutorial

Key concepts covered in this tutorial will be :

• What is V8?
• Setting up Node.JS understanding anatomy of a Node.JS program
• NPM and YARN
• First Node.JS program
• Exporting and Importing
• Paths in Node.JS
• Setting up folder structure for a Node Project
• Async Functions
• JS Event Loop
• Concept of threads
• Callbacks and Callback Hell
• Promises
• Async Await
• Higher Order Functions
• Closures
• Function Currying
• IIFEs
• this Keyword in Arrow Functions
• module.exports vs export
• require vs import
• module graphs and import order
• NPM package.json
• Installing packages using NPM
• Publishing package to NPM
• Client Server Architecture
• HTTP Basics
• REST APIs
• Building HTTP Server using HTTP API - 1
• Building HTTP Server using HTTP API - 2
• URLs and Query Strings Modules
• Buffers and String Decoders
• Process API in Node
• OS API
• Working with filesystems in Node
• Node.JS Events
• Event Emitters and Event Targets
• A deep dive into console
• Node.JS Command line in depth
• Multithreading with Node - Libuv
• Thread Pool and OS Operations
• Worker Threads in Node.JS
• Streams in Node.JS
• Webstreams in Node.JS
• Clustering in Node JS
• Cryptography in Node.JS
• Other Node Performance Optimization Techniques
• JEST Testing Framework Introduction
• Testing in Node.JS deep dive
• Deployment Intro and Preparing app for Deployment
• Deploying application to Heroku

Take Away Skills from This Node.js Tutorial

• Node.js is an open-source , cross-platform Javascript runtime environment that runs on chrome's V8 engine internally.
• NodeJs internally works with the help of chrome’s V8 engine and Libuv library. These help Nodejs to become non-blocking, concurrent, event-driven, and robust.
• For setting up the Node.js development environment: install Node.js, install a text editor and create a javascript file.
• Event-driven programming uses the concept of an event handler, i.e. function to be called when event triggers, and the main loop that listens for event triggers and calls associated event-handlers.
• Async function in javascript are a way to execute the asynchronous code in a synchronous and clear manner. They are generally a combination of generators and promises.
• The Event loop is an endless loop that waits for the events and executes them by pushing tasks into the call stack.
• Many fortune 500 organisations like Netflix, Trello, Uber and many more prefer Node.js to alternative frameworks.
• Node.js is ideally suited for use in real-time streaming or event-based applications like as chatting applications, real time game servers and collaborative atmospheres.
• The client-server architecture brings remote network management, a high level of processing to improve performance, and market-driven business.
• NPM, or Node Package Manager, is the Node.js package manager that comes pre-installed when you install Node.js on your machine. Yarn, or Yet Another Resource Navigator, is a package manager created by Facebook.
• Node.js, by default, follows the single threaded event loop based architecture. The cluster module permits the creation of child processes and utilization of multiple cores.
• The console module in node js exports two modules, which are the console class and global class instance.
• Heroku is a cloud platform that allows us to deploy, manage, provide data services for our node js app. We can automate the deployment process by connecting github repository with Heroku.
• There are five type of middleware in Node js - Application-level, Router-level, Third-party, Build-in type and Error-handling middleware.