How to use NPM (Node Package Manager)

How to Use npm (Node Package Manager)

npm (Node Package Manager) is a package manager for JavaScript, used to install and manage software packages. Here’s a basic guide on how to use it:

1. Installation

• Check if npm is already installed: Open your terminal or command prompt and type npm -v. If you see a version number, npm is installed.
• Install Node.js: If npm is not installed, download and install the latest version of Node.js from https://nodejs.org/. Node.js comes bundled with npm.

2. Basic Commands

• npm install <package-name>: Installs a package and saves it to the package-json file in your project’s root directory.
• Example: npm install express installs the popular web framework express.
• npm install <package-name>@<version>: Installs a specific version of a package.
• Example: npm install [email protected] installs version 4.17.1 of express.
• npm install -g <package-name>: Installs a package globally, making it available system-wide.
• Example: npm install -g typescript installs the TypeScript compiler globally.
• npm update <package-name>: Updates a package to its latest version.
• npm uninstall <package-name>: Removes a package from your project.
• npm list: Lists all installed packages.
• npm outdated: Shows outdated packages in your project.
• npm run <script-name>: Runs a script defined in the package.json file.

3. Creating a package.json File

• npm init: Initializes an empty package.json file in your project’s root directory. It will prompt you for basic project information.
• npm init -y: Initializes a package.json file with default settings.

4. Managing Dependencies

• package.json: This file stores information about your project, including dependencies.
• dependencies: Packages required for your project to run. These are listed in the package.json file.
• devDependencies: Packages used during development but not required in production. These are also listed in the package.json file.

5. Working with Scripts

• scripts: The package.json file allows you to define scripts that can be run using npm run.
• Example:

{
  "scripts": {
    "start": "node index.js",
    "build": "webpack --mode production"
  }
}

You can then run these scripts using:

• npm run start
• npm run build

6. Using npm with a package.json File

• When you run npm install, it uses the package.json file to determine which packages to install.
• If package.json doesn’t exist, npm will create one for you.

7. Using npm with yarn

While npm is widely used, another popular package manager called yarn is also available. yarn is known for its speed and deterministic builds. You can choose to use either one, but it’s generally recommended to stick to one for consistency within your project.

8. Resources

• Official npm website
• npm documentation
• Node.js documentation

This tutorial provides a basic introduction to npm. There are many more advanced features and concepts to explore. As you work with npm, you’ll encounter more specific commands and use cases based on your needs.