bf-workflows

NPM (Node Package Manager)

What is NPM?

NPM (Node Package Manager) is the default package manager for Node.js. It serves two primary functions:

Online Repository: NPM hosts a vast repository of open-source packages and modules for Node.js, which you can search and explore at search.npmjs.com.
Command Line Utility: NPM provides a command-line tool for managing packages, handling version control, and managing dependencies for Node.js projects.

Core Features

Package Management: Download and install packages from the NPM registry.
Version Control: Manage package versions and update dependencies.
Script Management: Run custom scripts defined in your package.json file.
Dependency Management: Automatically handle dependencies for your projects.

Basic NPM Commands

1. Check NPM Version

To check the installed version of NPM, use the following command:

npm --version

2. Initialize a New Project

To create a package.json file for a new Node.js project, run:

npm init

You will be prompted to enter details like the project name, version, and description. For a quicker setup with default values, use:

npm init -y

3. Install Packages

To install a package and add it to the dependencies section of package.json, use:

npm install <package-name>

To install a package as a development dependency, use:

npm install <package-name> --save-dev

4. Update Packages

To update a specific package to the latest version:

npm update <package-name>

To update all packages listed in package.json:

npm update

5. Install All Dependencies

To install all the dependencies listed in package.json, use:

npm install

6. Run Scripts

To run a script defined in the scripts section of package.json, use:

npm run <script-name>

For example, to start a development server with a script called start, you would run:

npm run start

7. Uninstall Packages

To remove a package and also remove it from package.json, use:

npm uninstall <package-name>

To uninstall a package but keep it in package.json, use:

npm uninstall <package-name> --no-save

8. View Package Information

To get detailed information about a package, including its dependencies, version, and more:

npm info <package-name>

9. Search for Packages

To search for packages in the NPM registry:

npm search <query>

10. Audit Dependencies

To check for vulnerabilities in your dependencies:

npm audit

To fix vulnerabilities:

npm audit fix

Advanced NPM Features

1. Workspaces

NPM Workspaces allow you to manage multiple packages within a single repository.

Define Workspaces in package.json:
```
{
  "workspaces": ["packages/*"]
}
```

Run Commands Across All Workspaces:

npm run <script> --workspace <workspace-name>

2. NPM Scripts

Scripts in package.json allow you to automate common tasks.

Example scripts Section:

"scripts": {
  "start": "node app.js",
  "test": "mocha test/",
  "build": "webpack"
}

Run start Script:
```
npm start
```

3. Creating and Publishing Packages

Create a Package:
- Create a directory and add a package.json file.
- Add your code and documentation.
- Use the following command to publish:
```
npm publish
```
Scope Packages:
- Use scoped packages to publish under a specific namespace, e.g., @username/package-name.
```
npm publish --access public
```

4. Global vs Local Packages

Install Package Globally:
```
npm install -g <package-name>
```
This makes the package available anywhere on your system.
Install Package Locally:
```
npm install <package-name>
```
This installs the package in the node_modules directory of your project.

5. Configuring NPM

To view or modify your NPM configuration settings:

View Configuration:
```
npm config list
```
Set a Configuration Value:
```
npm config set <key> <value>
```
View Global Configuration File:
```
npm config edit
```

Common Issues and Solutions

Issue: npm install Fails

Solution: Check for missing or incorrect permissions, update NPM, or clear the cache:
```
npm cache clean --force
```
Issue: Dependency Conflicts

Solution: Resolve version conflicts by reviewing the package.json or using npm outdated to check for updates.
```
npm outdated
```

Resources

Official NPM Documentation

This site is open source. Improve this page.