NPM (Node Package Manager) is a package manager for NodeJS modules. It helps developers manage project dependencies, scripts, and third-party libraries. By installing NodeJS on your system, NPM is automatically installed, and ready to use.
A package in NodeJS is a reusable module of code that adds functionality to your application. It can be anything from a small utility function to a full-featured library.
To start using NPM in your project, follow these simple steps
Step 1: Install NodeJS and NPMFirst, you need to install NodeJS. NPM is bundled with the NodeJS installation. You can follow our article to Install the Node and NPM- How to install Node on your system
Step 2: Verify the InstallationAfter installation, verify NodeJS and NPM are installed by running the following commands in your terminal:
node -v
npm -v
These commands will show the installed versions of NodeJS and NPM.
NodeJS NPM Version Step 3: Initialize a New NodeJS ProjectIn the terminal, navigate to your project directory and run:
npm init -y
This will create a package.json file, which stores metadata about your project, including dependencies and scripts.
Step 4: Install Packages with NPMTo install a package, use the following command
npm install <package-name>
For example, to install the Express.js framework
npm install express
This will add express to the node_modules folder and automatically update the package.json file with the installed package information.
Step 5: Install Packages GloballyTo install packages that you want to use across multiple projects, use the -g flag:
npm install -g <package-name>Step 6: Run Scripts
You can also define custom scripts in the package.json file under the "scripts" section. For example:
{
"scripts": {
"start": "node app.js"
}
}
Then, run the script with
npm startUsing NPM Package in the project
Create a file named app.js in the project directory to use the package
JavaScript
//app.js
const express = require('express');//import the required package
const app = express();
app.get('/', (req, res) => {
res.send('Hello, World!');
});
app.listen(3000, () => {
console.log('Server running at http://localhost:3000');
});
Now run the application with
node app.js
Visit http://localhost:3000 in your browser, and you should see the message: Hello, World!
Managing Project Dependencies 1. Installing All DependenciesIn a NodeJS project, dependencies are stored in a package.json file. To install all dependencies listed in the file, run:
npm install
This will download all required packages and place them in the node_modules folder.
2. Installing a Specific PackageTo install a specific package, use:
npm install <package-name>
You can also install a package as a development dependency using:
npm install <package-name> --save-dev
Development dependencies are packages needed only during development, such as testing libraries.
To install a package and simultaneously save it in package.json file (in case using NodeJS), add --save flag. The --save flag is default in npm install command so it is equal to npm install package_name command.
Example:
npm install express --saveUsage of Flags:
3. Updating PackagesNote: If there is a package.json file with all the packages mentioned as dependencies already, just type npm install in terminal
You can easily update packages in your project using the following command
npm update
This will update all packages to their latest compatible versions based on the version constraints in the package.json file.
To update a specific package, run
npm update <package-name>4. Uninstalling Packages
To uninstall packages using npm, follow the below syntax:
npm uninstall <package-name>
For uninstall Global Packages
npm uninstall package_name -gPopular NPM Packages for NodeJS
NPM has a massive library of packages. Here are a few popular packages that can enhance your NodeJS applications
Packages
Description
A fast, minimal web framework for building APIs and web applications.
A MongoDB object modeling tool for NodeJS.
A utility library delivering consistency, customization, and performance.
A promise-based HTTP client for making HTTP requests.
A popular front-end library used to build user interfaces.
Loads environment variables from a .env file into process.env.
Automatically restarts the server during development when file changes are detected.
A JavaScript testing framework designed to ensure correctness of any NodeJS code.
Enables real-time, bidirectional communication between web clients and servers.
Versioning in NPMNPM allows you to manage package versions. This is important when you want to ensure that a specific version of a library is used across all environments.
Install a Specific Version
To install a specific version of a package, use:
npm install <package-name>@<version>
For example:
npm install express@4.17.1
This will install version 4.17.1 of Express, regardless of the latest version.
Using Semantic Versioning to manage packagesWhile NPM is the default package manager for NodeJS, there are alternatives like Yarn and pnpm. These tools aim to provide faster package installations and additional features but work in similar ways to NPM.
Best Practices for Using NPM in NodeJS ProjectsNPM (Node Package Manager) is an essential tool for managing NodeJS packages and dependencies, making development more efficient and scalable. It allows developers to install, update, and manage libraries easily, supporting both local and global installations. With features like version control, dependency management, and automation scripts, NPM enhances the development workflow.
Node.js | NPM (Node Package Manager)
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