Day 3 of NodeJS||Important Modules

Hey reader👋Hope you are doing well😊
In the last post we have discussed about how to get started with NodeJS. In this post we are going to see Modules in NodeJS.
So let's get started🔥

What are Modules?

Consider modules as JavaScript libraries that provides different functionalities for development. Modules can be a single file or a collection of multiple files/folders. The reason programmers are heavily reliant on modules is because of their reusability as well as the ability to break down a complex piece of code into manageable chunks.
Node.js treats each file in a Node project as a module that can export values and functions from the file.

Here utility.js is a module but it is not exporting anything right now.

exports in NodeJS -:
We can export functions and properties either by using module.exports or exports. The exports keyword is a reference to the exports object in the modules object.

Different types of NodeJS Modules

There are three types of modules-:

• Core Modules

• Local Modules

• Third Party Modules

Core Modules

Node.js has many built-in modules that are part of the platform and come with Node.js installation. These modules can be loaded into the program by using the required function.
const module=require(module_name)
The require() function will return a JavaScript type depending on what the particular module returns.
Some of the Core modules are -:

• http -: creates an HTTP server in Node.js.

• https -: creates an HTTPs server in Node.js.

• fs -: used to handle file system.

• path -: includes methods to deal with file paths.

• os -: provides information about the operating system.

• process -: provides information and control about the current Node.js process.

• querystring -: utility used for parsing and formatting URL query strings.

• url -: module provides utilities for URL resolution and parsing.

• assert -: set of assertion functions useful for testing.

• tls -: to implement TLS and SSL protocols.

• net -: to create servers and clients.

• crypto -: to handle OpenSSL cryptographic functions.
  These are some of the important built-in modules.

Local Modules

We can create our own module too apart from built-in and third party modules.
Let's create a simple calculation module-:

• Step1 -> Create Calculation.js file-:
  
  Let me show you module object here-:
  
  You can see that we are exporting four functionalities here.

• Step 2 -> Use the module in script.js file -:
  
  Here we have imported the module using require keyword.

• Output ->
  
  Easy huh🙃

Third-party modules

Third-party modules are modules that are available online using the Node Package Manager(NPM). These modules can be installed in the project folder or globally. Some of the popular third-party modules are Mongoose, express, angular, and React.
Example -:

• npm install express
• npm install mongoose
• npm install -g @angular/cli

So this was all about modules. I hope you have understood this blog. In the next blog we will see one another way of using module in a file. Till then stay connected and don't forget to follow me.
Thankyou🤍