What is Node.js – A Brief Introduction

In this article, you will get a brief introduction of various node js topics. Let’s start!!!!

What is nodejs?

It is a server side runtime environment for javascript. It is open source and it was developed by Ryan Dahl in 2009. Node js runs on windows, linux, macOS and all the popular operating systems. Nodejs is basically a runtime environment with a javascript library.

What can nodejs do?

• Generate dynamic content.
• All the operations on file.
• Manipulate databases.

What is the nodejs file?

• Contains tasks that will execute.
• Initialized in server
• Has .js file extension

Why nodejs?

Nodejs eliminates waiting time; it is single threaded, non-blocking asynchronous, making it very memory efficient.

Features of Node.js

1. Asynchronous Event Driven:

Nodejs after starting its server it initializes all variables, functions and then keeps waiting for an event to occur. That is why node js applications are event-driven.

These functions do not block the thread. Even when a function is not completely executed other codes can do their task simultaneously.

2. Fast:

Its execution of code is fast as it is built using v8 javascript engine.

3. Single-Threaded and scalable:

It is a single threaded and due to its non blocking mechanism it is highly scalable.

4. No Buffering:

There is no buffering in nodejs. It directly outputs the information.

5. License:

It is released under the MIT License.

Advantages of Nodejs

1. Scalable:

It is easy to scale both horizontally and vertically.

2. Fast:

Its execution of code is fast as it is built using v8 javascript engine.

3. Real-time apps:

Useful in making chat and gaming applications because of its faster synchronizations.

4. Catching single module:

Catching a single module is possible in nodejs.

5. Easy to learn:

It uses javascript, therefore it becomes easy for front end engineers to learn nodejs .

6. Streaming:

Streaming audio and video files are very fast in nodejs. So nodejs can be used for developing such kind of applications.

7. Support:

Most of the big companies are using it as it helps them to combine the frontend and backend team into a single unit.

Applications of Nodejs:

Applications of Nodejs are:

• Real time chats: Since node js is fast therefore real time chat applications use it.
• Streaming apps: Nodejs along with socket is used for making video streaming applications.
• Api based applications: Nodejs can handle multiple requests easily so many APIs are developed using nodejs.

Which organizations use Nodejs?

Microsoft, Paypal, Godaddy, Uber and many other big companies use node js.

Where to use nodejs?

If your application highly depends on the below topics than it is better to use nodejs

• I/O bound application
• Data Streaming application
• Real time application
• JSON API
• Single page application(SPA)

Where shouldn’t you use node js?

If your application is CPU intensive then it is recommended to not develop it using nodejs.

Initiate Nodejs file:

To run a nodejs file run the below command:

Node filename.js

What NPM is?

Npm stands for node package manager. It is the most popular package manager for node.js. It helps us to install all the different kinds of modules available for node.js. Npm is like a playstore for node.js. Whenever we require any package in our project we download it from npm.

Modules:

Modules are encapsulated code blocks that communicate with an external application. These can be a single file or a collection of multiple files/folders. Modules are reusable.

Types of Modules:

There are three types of modules

1. Core Modules: Modules which are part of nodejs and come with the Node.js installation process are known as core modules.

2. Local Modules: Modules which are made by the user are local modules.

3. Third-party Modules: Modules that are available online and are installed using the npm are third party modules.

Event:

Event module in nodejs is a built-in module, this module contains the event emitter class which implements event driven programming.

To use this module in our file we use the require() function. Event emitter class generates the events in nodejs. The event emitter class and the javascript callbacks handle the event.

REPL Environment:

The four parts of Repl are as follows:

1. Read: Parses the user input javascript, and stores it in memory.
2. Eval: Evaluates the parsed javascript.
3. Print: The result of the evaluation is shown.
4. Loop: Again starts reading.

What is the Callback function?

When a task completes, a function is called and this function is callback function.

Synchronous functions:

Functions that block the thread until it executes completely are synchronous functions.

Asynchronous functions:

Even when a function is not completely executed other codes can do their task simultaneously.

Event Loop:

Node js uses javascript and we know that javascript is single threaded and synchronous than how node js maintains concurrency? In order to achieve it, nodejs has events and callbacks. Event loop is an infinite loop and in each iteration it checks the event queue for any triggered event, if found it then executes it and removes it from the queue.

What is a stream?

Streams are objects that we use to read data from a source or write data to a destination in sequential fashion.

Global Object:

Global object means that these objects are accessible from anywhere, you can use this object from any module in your project.

Web server and its working:

Web servers are programs that deal with http requests. The http requests sent by the client are handled by the web server and it then gives a response to the clients. A web server generally provides the html, stylesheets, and images.

What is express?

It is a framework for nodejs. Express allows you to dynamically render html pages. It also allows you to perform different actions based on different html methods.

Rest architecture:

It is a web standards based architecture that uses HTTP Protocol. Every component is a resource and these resources are accessible by an interface using HTTP methods.

Components of nodejs application:

1. Importing modules: To include anything in nodejs we use the require() function.

2. Creating server: This will listen to the client requests. Mostly the http methods create the server.

3. Request and response: The server will listen to the http requests made by the client and in turn will send a response for that request.

Why use MySQL with nodejs?

• It is a free database.
• It supports most of the operating system
• Fast even when it has large data

Conclusion

In this article we discussed what is node js, where to use it and what you can learn from this series of articles, so check out the individual topic articles of nodejs to learn more with code and examples.