In this section, we will explore how to install and use packages in Node.js using the Node Package Manager (NPM). Packages are reusable pieces of code that can be included in your Node.js projects to extend functionality without having to write everything from scratch.

1. NPM (Node Package Manager): A package manager for JavaScript that allows you to install, share, and manage dependencies in your Node.js projects.
2. Package.json: A file that holds metadata about your project and its dependencies.
3. Installing Packages: Using NPM commands to add packages to your project.
4. Using Packages: Requiring and utilizing installed packages in your code.

Before you can install packages, you need to initialize a Node.js project. This creates a package.json file that will keep track of your project's dependencies.

The -y flag automatically answers "yes" to all prompts, creating a package.json file with default values.

The package.json file is crucial for managing your project's dependencies. Here is a basic example:

• name: The name of your project.
• version: The current version of your project.
• dependencies: An object where installed packages and their versions are listed.

To install a package, use the npm install command followed by the package name. For example, to install the popular lodash library:

This command does the following:

• Downloads the lodash package and its dependencies.
• Adds lodash to the dependencies section of your package.json.
• Creates a node_modules directory where the package is stored.

Your package.json will now include:

To use an installed package in your project, you need to require it in your code. Create an index.js file and add the following code:

Dev dependencies are packages that are only needed during development (e.g., testing libraries). To install a package as a dev dependency, use the --save-dev flag:

This will add mocha to the devDependencies section of your package.json:

To remove a package, use the npm uninstall command followed by the package name:

This will:

• Remove the lodash package from the node_modules directory.
• Remove lodash from the dependencies section of your package.json.

1. Initialize a new Node.js project.
2. Install the axios package, which is used for making HTTP requests.
3. Create a script that makes a GET request to https://jsonplaceholder.typicode.com/todos/1 and logs the response.

Solution:

1. Initialize the project:

2. Install axios:

3. Create index.js and add the following code:

4. Run the script:

Expected Output:

• Forgetting to Initialize the Project: Always run npm init before installing packages to ensure package.json is created.
• Not Saving Dependencies: Use --save (default in npm 5+) or --save-dev to ensure dependencies are listed in package.json.
• Incorrect Package Names: Double-check the package name before installing to avoid typos.

In this section, you learned how to initialize a Node.js project, install and use packages, and manage dependencies using NPM. These skills are fundamental for any Node.js developer, as they allow you to leverage the vast ecosystem of JavaScript libraries to build robust applications efficiently. Next, we will dive into creating and publishing your own packages.