Types of Modules in Node.js<\/h2>\n\n\n\n
We can divide Node modules into three types based on how they are offered or how they interact with the application.<\/p>\n\n\n\n
- \n
- Core Modules<\/li>\n\n\n\n
- Local Modules<\/li>\n\n\n\n
- Third-Party Modules<\/li>\n<\/ol>\n\n\n\n
Let’s look at each of them one by one.<\/p>\n\n\n\n
Node.js Core Modules<\/h2>\n\n\n\n
Node.js Core Modules are the modules pre-built with Node.js. These are pre-written in the Node.js system and whenever you install Node.js they will be enclosed as part of the installation.<\/p>\n\n\n\n
Some of the most popular core modules are:<\/strong><\/p>\n\n\n\n
- \n
- HTTP: Used for making all types of HTTP requests such as GET, POST, PATCH, DELETE, etc<\/a><\/li>\n\n\n\n
- FS: A File System Module is used for working with files present in the operating system.<\/a><\/li>\n\n\n\n
- Path: It can be used to work with file paths.<\/a><\/li>\n\n\n\n
- Child Process: If you need to code on the operating system\u2019s process level, you can use this module.<\/a><\/li>\n<\/ul>\n\n\n\n
Using Node.js Built-in Modules <\/h3>\n\n\n\n
To use the core module it is not necessary to install it, you just need to import it. You can simply use the require() <\/strong>function and pass in that module\u2019s name. The require() <\/strong>function will return the module and save it in a variable.<\/p>\n\n\n
\nconst path = require('path')\n<\/pre><\/div>\n\n\nExample:<\/strong><\/p>\n\n\n
\nconst path = require('path')\n \nconst name = 'Sushant'\nconst output = path.join('\/', 'Users', name, 'test.txt') \/\/'\/Users\/Sushant\/test.txt'\n \nconsole.log(output)\n<\/pre><\/div>\n\n\nHere we have imported the \u201cpath\u201d module, we have not installed it because it is one of the Node.js core modules. Then we used its method join() to combine multiple path segments into one and console log the output.<\/p>\n\n\n\n
Output:<\/strong><\/p>\n\n\n\n
![\"Output](\"https:\/\/codeforgeek.com\/wp-content\/uploads\/2024\/01\/Node.js-Core-Modules.png\")
<\/figure>\n\n\n\nNode.js Local Modules<\/h2>\n\n\n\n
Sometimes developer needs the same functionality in different places in their software so they create their own local modules. Local Modules <\/strong>are those modules that are created by the developer and are not pre-built in Node.js. They are used to make development life more effortless and fast because they automatically decrease code length. Let\u2019s create our own local module.<\/p>\n\n\n\n
Creating and Using Local Modules in Node.js<\/h3>\n\n\n\n
To use a local module, we first have to create it. Below is an example of creating and using a local module.<\/p>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\n
Let’s create a local module “greetingsModule.js” and then try to import and use it inside the main server file. <\/p>\n\n\n
\n\/\/ greetingsModule.js\n\/\/ Simple Greetings Module\n\nexports.sayGoodMorning = function(name){\n console.log(`Good Morning ${name}!`)\n}\n\nexports.sayGoodAfternoon = function(name){\n console.log(`Good Afternoon ${name}`)\n}\n\nexports.sayGoodNight = function(name){\n console.log(`Good Night ${name}`)\n}\n<\/pre><\/div>\n\n\nIn the above code, we have created three functions and exported them using the exports keyword. This keyword will export these functions so that they can be imported to use in other files as modules.<\/p>\n\n\n
\nconst greetingsModule = require('.\/greetingsModule')\n\ngreetingsModule.sayGoodMorning('Sushant')\ngreetingsModule.sayGoodAfternoon('Sushant')\ngreetingsModule.sayGoodNight('Sushant')\n<\/pre><\/div>\n\n\nHere, we have imported the file created in the above step using the require()<\/strong> method. Then used the dot operator and called all three functions. The output of all three functions can be shown below.<\/p>\n\n\n\n
Output:<\/strong><\/p>\n\n\n\n
![\"Output](\"https:\/\/codeforgeek.com\/wp-content\/uploads\/2024\/01\/Node.js-Local-Modules.png\")
<\/figure>\n\n\n\nNode.js Third-Party Modules<\/h2>\n\n\n\n
Most of the time coding requires several kinds of functionality. Now to do this we have two methods. The first method is we can implement complete functionality on our own and the second method is we can use any third-party module which will provide us with the same functionality. We usually go for the second option. The 3rd party modules are libraries that are publicly available and developed by someone else. These are found on repositories such as npm<\/strong><\/a>.<\/p>\n\n\n\n
Some of the most popular third-party modules are: <\/strong><\/p>\n\n\n\n
- \n
- Mongoose<\/a><\/li>\n\n\n\n
- Multer<\/a><\/li>\n\n\n\n
- Body Parser<\/a><\/li>\n\n\n\n
- JSON Web Token<\/a><\/li>\n<\/ul>\n\n\n\n
Installing and Using Third-Party Modules with NPM<\/h3>\n\n\n\n
To use third-party NodeJS modules, it is necessary to install them first. To install any third-party module we need a package manager. The most popular package manager is npm<\/strong><\/a>. When you install Node.js in your system, npm is also automatically installed.<\/p>\n\n\n\n
Below is the command to install any package from npm directly into your project.<\/p>\n\n\n
\nnpm install express\n<\/pre><\/div>\n\n\n
The above command will install a module \u201c<\/strong>express\u201d<\/strong> in your project.<\/p>\n\n\n\n
Also, we can install the module globally so that it can be accessed by any of your projects, you can use the same command with an additional attribute \u201c-g\u201d<\/strong> to install a module globally.<\/p>\n\n\n
\nnpm install -g express\n<\/pre><\/div>\n\n\n
Here -g means global installation.<\/strong><\/p>\n\n\n\n
After installing a third-party module locally or globally, you can import it into your project using require()<\/strong>, just like we imported the core module or a local module.<\/p>\n\n\n
\nconst express = require('express')\n<\/pre><\/div>\n\n\nExample:<\/strong><\/p>\n\n\n\n
Let’s use the express module and create a simple Node.js application that sends an HTML file for the home page containing an h1 tag with the message \u201cHome\u201d.<\/p>\n\n\n
\nconst express = require('express');\n \nconst app = express();\n \napp.get('\/', (req, res) => {\n res.sendFile(__dirname + '\/index.html');\n});\n \napp.listen(3000);\n<\/pre><\/div>\n\n\nHere we have imported the \u201cexpress\u201d module that we already installed. Then we used its \u201csendFile()\u201d method to load and send an HTML file to the client when the request was received for the home(\u201c\/\u201d) route.<\/p>\n\n\n\n
- Multer<\/a><\/li>\n\n\n\n
- FS: A File System Module is used for working with files present in the operating system.<\/a><\/li>\n\n\n\n
- HTTP: Used for making all types of HTTP requests such as GET, POST, PATCH, DELETE, etc<\/a><\/li>\n\n\n\n
![\"Output](\"https:\/\/codeforgeek.com\/wp-content\/uploads\/2024\/01\/Node.js-Third-Party-Modules.webp\")
<\/figure>\n\n\n\n