NPM Node Package Manager Modules | NPM Tutorial for Beginners

Summary

This tutorial introduces Node Package Manager (npm) and demonstrates how to manage Node.js packages effectively. Viewers learn to install Node.js and npm, explore packages like axios, date-fns, and uuid, and differentiate between global, production, and development dependencies. The video covers initializing a project with `npm init`, adding dependencies, using scripts in `package.json` for running and developing applications, and understanding semantic versioning. It also explains managing node_modules, using `.gitignore`, updating packages safely, and uninstalling dependencies. Practical examples with `nodemon`, date formatting, and generating unique IDs provide hands-on experience for building and maintaining Node.js projects efficiently.

Takeaways

• 😀 npm stands for Node Package Manager and comes installed with Node.js, allowing developers to use thousands of third-party packages.
• 📦 npm packages are reusable modules created by other developers, which help avoid reinventing the wheel in your projects.
• 💻 Global packages, like nodemon, can be installed with `npm install -g <package>` and used directly from the command line.
• ⚡ Nodemon is a development tool that automatically restarts your Node.js server when files change, improving workflow efficiency.
• 📝 Initialize a project with `npm init` to create a `package.json` file, which tracks project dependencies and metadata.
• 🗂️ Always add `node_modules` to `.gitignore` to prevent committing large dependency folders to your repository.
• 🔧 Production dependencies are installed with `npm i <package>` and dev dependencies with `npm i <package> -D` for development-only tools.
• 🛠️ npm scripts in `package.json` can automate commands, such as `start` for production and `dev` for development environments.
• 📊 Semantic versioning helps manage package updates safely: `^` for minor/patch updates, `~` for patch updates, and exact versions to prevent breaking changes.
• ❌ Uninstalling a package with `npm rm` removes it from dependencies but does not automatically update scripts in `package.json`.
• 📚 Always refer to npm documentation and package-specific docs for installation instructions, usage, and updates.
• 🆔 Packages like `uuid` can generate unique identifiers, useful for logging events or tracking data entries.
• 📅 Date handling packages like `date-fns` simplify date formatting and manipulation in Node.js applications.

Q & A

What is npm and how is it related to Node.js?

npm, or Node Package Manager, is a package manager that comes installed with Node.js. It allows developers to install, manage, and share reusable packages created by third-party developers for use in Node.js applications.

What is the difference between a Node.js core module and an npm package?

Node.js core modules are built into Node.js itself, while npm packages are third-party modules created by other developers that can be installed and used in your projects.

How do you install a package globally and why would you do this?

To install a package globally, use `npm install -g package-name`. Global installations are useful for tools that you want to access from the command line across multiple projects, such as `nodemon`.

What is the purpose of nodemon and how does it work?

Nodemon automatically restarts a Node.js application when files are changed, saving developers from manually stopping and restarting the server each time they make changes.

How do you initialize a new Node.js project with npm?

You initialize a new project by running `npm init` and following the prompts, or `npm init -y` to accept default settings. This creates a `package.json` file which stores project metadata and dependencies.

What is the difference between dependencies and devDependencies in npm?

Dependencies are required for the application to run in production, while devDependencies are only needed during development, such as testing or build tools like `nodemon`.

How can you use an installed npm package in your code?

You can import an installed package using `require` in CommonJS or `import` in ES6. For example: `const { format } = require('date-fns');` allows you to use the `format` function from the `date-fns` package.

What are npm scripts and how do you use them?

npm scripts are custom commands defined in `package.json` under the `scripts` section. You can run them with `npm start` or `npm run <script-name>`. For example, a 'dev' script can run `nodemon index.js` to automatically restart the server during development.

How does semantic versioning work in npm?

Semantic versioning follows the format `major.minor.patch`. Prefixes like `^` allow updates to minor and patch versions, `~` allows only patch updates, and no prefix installs the exact version. This helps prevent breaking changes from major version updates.

How do you uninstall an npm package and what should you be aware of?

You can uninstall a package using `npm uninstall package-name` for production dependencies or `npm uninstall --save-dev package-name` for dev dependencies. Uninstalling a package does not automatically remove it from npm scripts, so you may need to manually update scripts in `package.json`.

Why should you include `node_modules` in `.gitignore`?

The `node_modules` folder contains all installed packages and can become very large. Including it in `.gitignore` prevents it from being uploaded to version control, while the `package.json` file ensures others can install the correct dependencies.

How can you update npm packages while respecting version rules?

You can run `npm update`, which checks for newer versions of installed packages while respecting semantic versioning rules defined in `package.json`, such as caret `^` or tilde `~` constraints.

How can you find and choose npm packages for your project?

You can search for packages on [npmjs.com](https://www.npmjs.com/) using keywords. Packages are ranked by popularity, quality, and maintenance. Each package provides installation instructions, documentation, and links to its repository.