npm and npx: A Simple Guide for Everyone

If you have ever worked with JavaScript or Node.js, you have probably seen the words "npm" and "npx" many times. They look similar, but they do different things. This article will explain both in simple terms, so anyone can understand them, even if you are new to coding.

What is npm?

npm stands for Node Package Manager. It comes installed automatically when you install Node.js on your computer.

Think of npm as a store. In this store, you can find small pieces of code called packages (or libraries) that other developers have already written. Instead of writing everything from scratch, you can download these packages and use them in your own project.

For example, if you need a package to format dates in JavaScript, you do not have to write that code yourself. Someone has probably already built it and shared it on npm. You just download it and use it.

npm has three main parts:

1. A website (npmjs.com) where you can search for packages.
2. A command line tool that lets you install and manage packages from your terminal.
3. A registry, which is a huge online database that stores all these packages.

Why do developers use npm?

Here are the main reasons:

• It saves time. You do not need to build every tool or function from zero.
• It keeps projects organized. npm tracks every package your project uses, along with the exact version.
• It makes sharing easy. If you build something useful, you can publish it on npm so others can use it too.
• It handles updates. npm can help you update packages when new versions come out.

Getting started with npm

To check if npm is installed on your computer, open your terminal and type:

npm -v

This will show you the version number. If you see a version, npm is ready to use.

Starting a new project

When you start a new project, you usually run:

npm init

This command asks you a few questions (like project name and version) and then creates a file called package.json. This file is very important. It works like a summary sheet for your project. It lists the project's name, version, and all the packages it depends on.

If you want to skip the questions and just create the file with default values, use:

npm init -y

Installing a package

To add a package to your project, use:

npm install package-name

For example, to install a popular package called axios (used for making web requests), you would type:

npm install axios

After running this, two things happen:

1. A folder called node_modules is created. This folder holds the actual code of the packages you installed.
2. Your package.json file is updated to list axios as a dependency.

You will also see a file called package-lock.json. This file locks the exact versions of every package (and their smaller dependencies) so that your project works the same way on any computer.

Installing all packages for a project

If you download a project that already has a package.json file but no node_modules folder, you can install everything it needs with just:

npm install

npm will read the package.json file and download all the listed packages automatically.

Removing a package

If you no longer need a package, you can remove it with:

npm uninstall package-name

Updating packages

To update your packages to newer versions, you can run:

npm update

What is npx?

Now let us talk about npx. npx stands for Node Package Execute. It comes bundled with npm, so if you have npm, you already have npx too.

npx solves a different problem. Sometimes you do not want to install a package permanently. You just want to run it one time.

Without npx, if you wanted to use a tool like create-react-app (a tool that sets up a new React project for you), you would need to install it globally on your computer first:

npm install -g create-react-app

This has some downsides:

• It takes up space on your computer.
• The tool can become outdated if you do not update it often.
• You end up with many global packages you rarely use.

With npx, you can run the same tool without installing it permanently:

npx create-react-app my-app

npx will download the tool, run it one time, and then not keep it installed globally. This keeps your computer clean and makes sure you are always using the latest version of the tool.

When should you use npx?

Here are common situations where npx is useful:

• Running a tool once, like generating a new project (npx create-react-app, npx create-next-app).
• Testing a package before deciding to install it in your project.
• Running a script that is already inside your project's node_modules, without typing the full path.

For example, if your project has a package called jest (used for testing) installed locally, you can run it with:

npx jest

This works even though jest was not installed globally on your system. npx knows to look inside your project's node_modules folder first.

npm vs npx: The Simple Difference

A simple way to remember it: npm is for keeping, npx is for running.

A Quick Example to Tie It Together

Imagine you want to start a new Node.js project and add a package for handling dates.

# Step 1: Create a new project folder and move into it
mkdir my-project
cd my-project

# Step 2: Set up the project with a package.json file
npm init -y

# Step 3: Install a package to handle dates
npm install dayjs

# Step 4: Use npx to quickly check your project for outdated packages
npx npm-check-updates

In this example, npm was used to set up the project and install a package we plan to use often. npx was used to run a helpful tool one time, without adding it permanently to the project.

Common Mistakes to Avoid

• Deleting node_modules without reason. If something goes wrong, you can safely delete this folder and run npm install again to rebuild it.
• Ignoring package-lock.json. This file should be kept and shared with your team. It keeps everyone using the same package versions.
• Installing everything globally. Try to use npx for one-time tools instead of installing many global packages.
• Not checking package trust. Before installing a package, check how popular and well-maintained it is on npmjs.com.

Final Thoughts

npm and npx work together to make JavaScript development easier. npm helps you manage the packages your project depends on, while npx helps you run tools quickly without cluttering your system. Once you understand the difference, you will find it much easier to set up projects, use helpful tools, and keep your work organized.