Node.js Modules

JavaScript engines improved a lot as browsers vied to provide customers with the greatest performance. Leading browsers put a lot of effort into figuring out how to make JavaScript run more quickly and provide better support. Node.js was therefore created at the appropriate time. Numerous methods for JavaScript server-side development were established, as well as creative thinking that has benefited many developers. The fact that Node.js supports hundreds of open-source libraries, the bulk of which are hosted on the npm website, is one of the main reasons for its prominence amongst developers. In this article, we will be throwing light on the Node.js module, what it is, its types, how to create one, and more. So, let's get started, shall we?

What is Node js?

Node.js is a very powerful open-source JavaScript environment that is utilized to develop single-page applications, video streaming websites, instant chat applications, and a variety of other I/O-heavy web projects. It was developed using the JavaScript V8 Engine in Google Chrome and is used by both well-known businesses and fresh startups.

Because Node.js is open-source and cost-free, many developers love to use it. Since it has more advantages than other server-side platforms like Java or PHP, it is a superior choice.

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Introduction to Node.js Module 

A Node.js module is a basic or complicated piece of functionality that is arranged in one or more JavaScript files that can be utilized throughout the entire Node.js application.

Since each Node.js module maintains its unique context, they cannot conflict with one another or contaminate the global scope. Additionally, every module can be put in a distinct .js file within a different subdirectory.

Modules' reusability and capacity to divide a complicated piece of code into understandable pieces are two reasons why programmers rely on them so heavily.

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Node js Module types

In this section, we will be learning about the three most popular types of Node.js, namely core modules, local modules, and third-party modules. Let’s discuss about each one of them one by one.

Core Modules:

The basic minimal Node.js features are included in the core modules. These essential modules are built into the binary distribution of Node.js and are loaded upon startup. But to employ it on your app, you must initially import the core module. You must first import Node.js core or NPM modules using the require() function, as demonstrated in the example below, before utilizing them.

var module = require("module name");

Enter the module name in the require() function using the syntax shown above. Based on what the given module returns, the require() function may return an object, a function, a property, or any other JavaScript type.

Local Modules:

In your Node.js application, local modules are those that you have built locally. These modules contain various program capabilities in independent files and folders. Additionally, you can package it and make it available via NPM for usage by the Node.js community. For instance, you can write a module for connecting to MongoDB and retrieving data, that can subsequently be utilized across your application.

Let's create a module called summation of adding two numbers, and subsequently incorporate it in our index.js file so that we may utilize it.

Code for exporting and building local modules:

exports.add=function(n,m){

    return n+m;

};

To render properties and methods accessible beyond the file, use the exports keyword.

We utilize the need method to incorporate the add function in our index.js file.

Third-Party Modules:

Online modules accessible through the npm are referred to as third-party modules. Such modules can be downloaded globally or in the project folder. The notable third-party modules are react, angular, express, and mongoose.

How to create Node js module

Now that we have gotten a basic idea of what nodejs modules are and their types, we are now ready to learn how to create one.

Packages of the Node.js module type can be published via npm.

1. Run npm init on the command line in the root directory of your Node.js module to create a package.json file:

  • Run the command npm init --scope=@scope-name for scoped modules.
  • Run npm init for unscoped modules.

2. Respond to the primary field and the two mandatory fields (name and version) as follows:

  • name: Your module's name.
  • version: The first version of the module. We advise beginning with version 1.0.0 and adhering to the semantic versioning principles.

Build the file that will be loaded when a different program needs your module.

Add a function to the file as a property of the exports object. By doing this, other programs will be able to use the function:

exports.printMsg = function() {

  console.log("ABC");

}

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Node js file system module

Node.js includes a built-in module named FS to manage file actions like creating, reading, deleting, etc. Node.js provides wrappers around the common POSIX functions to provide file I/O capabilities. Based on user needs, most file system operations can be either synchronous or asynchronous. Employ the require() function to use this File System module:

var fs = require('fs');

A popular use for File System module:

  • Read Files
  • Write Files
  • Append Files
  • Close Files
  • Delete Files

Node js URL module

The 'url' module offers tools for parsing and resolving URLs. The URL class is present on the global object, and the getters and setters on the class prototype execute the attributes of URL objects.

An API integrated into the URL module, the new URL() method builds a new URL object by parsing the input in reference to the base. If the base is supplied as a string, the equivalent of the new URL will be processed.

How to test your module

1. Put your package online with npm:

  • Run npm publish for unscoped and private packages.
  • Use npm publish —access public for scoped public packages.

2. Build a new test directory on the command line separate from your project directory.

  • mkdir test-directory

3. For switching to the new directory:

cd /path/to/test-directory

4. Install the module in the test directory:

npm install 

5. Make a test.js file in the test directory that uses your module as a method call and requires it.

6. Execute the node test.js command line program. The message sent to the console.log will be displayed.

Important Node js modules and their uses

We have listed down some of the most essential node js modules along with their respective uses. Note that this list is in no way exhaustive and we have many more nodejs modules in the picture. 

Image Manipulation

GraphicsMagick and ImageMagick are two well-known software for producing, editing, composing, and transforming images. Both software can be used straight from inside your JavaScript code with the help of the Node.js module gm. The module allows all common image operations, including, but not limited to, resizing, clipping, and encoding.

Generating Sprite Sheets

Sprite sheets, which are bitmap files with several little pictures (such as icons), are frequently employed to minimize image download time and accelerate page loading. Manually creating sprite sheets is highly time-consuming, but you can automate the procedure with spritesmith. This program takes a file as input and creates a single sprite sheet from every image inside. Additionally, it creates a JSON file that you can immediately copy into your CSS code that includes all of the coordinates for all of the photos in the final image.

Processing Markdown Files

When writing on the web, Markdown is a common format to use. Marked deserves a look if you've ever wished for processing the markdown data programmatically (i.e., create your own markdown editor). It generates the proper HTML code after receiving a string of markdown code as input. Even more customization of that HTML output is available by using unique renderers.

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Conclusion

With this, we have come to an end for this article. We hope that by now you must have come to a basic understanding of what Node.js modules are, their various types, how to create and test them, and the important ones that are currently in use. 

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Amani
Amani
Research Analyst
As a content writer at HKR trainings, I deliver content on various technologies. I hold my graduation degree in Information technology. I am passionate about helping people understand technology-related content through my easily digestible content. My writings include Data Science, Machine Learning, Artificial Intelligence, Python, Salesforce, Servicenow and etc.

The basic minimal Node.js features are included in the core modules. These essential modules are built into the binary distribution of Node.js and are loaded upon startup. But to utilize it in your application, you must first import the core module.

Some of the essential core modules are:

  • http
  • url
  • querstring
  • path
  • fs
  • util

In JavaScript, a module is essentially a file with associated code. The import and export keywords in JavaScript are used to distribute and receive functions among several modules, respectively. A variable, method, class, or object is made available to additional modules using the export keyword.

A callback is a function's asynchronous replacement. Once a task is finished, a callback function is invoked. Callbacks are heavily utilized by Node. Callbacks are supported by every single API that is part of Node.js.

In the request-response cycle of an application, the middleware function in node.js is a method with complete accessibility for making an object request, receiving an object response, and continuing to the subsequent middleware function.

Owing to its single-threaded nature, Node. js is typically used for non-blocking, event-driven servers. Although it was created with real-time, push-based architectures in mind, it is utilized for conventional web pages and back-end API services.