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How to create NPM package

How to create NPM package

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Shailendra Sonar
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4 min read

NPM is the largest software registry on the internet. There are over a million packages in the NPM Library.

How to Choose a Name For Your NPM Package

The first thing you need to do before creating your package is to choose a name.

This is important because your package needs to have a unique name.

You should choose a name that has not been used already.

When you decide on a name, go to the NPM registry and run a search.

Be sure there's no exact match to the name you chose (or a match that is too similar).

How to Create a NPM Package

Follow the steps below to create your package.

1. Install Node

If you do not already have Node installed, you should go ahead and install it. You can visit the official website to download and install Node.js. NPM comes pre-installed with Node.

2. Initialize a Git Repository

Create a new project folder for your package and navigate into the folder. Then, run the following command in your terminal:

git init

This will help you track the changes you make to your package. Also, make sure you have a remote version of your repository on GitHub (or your preferred hosting service).

3. Initialize NPM in Your Project

To do this, navigate to the root directory of your project and run the following command:

npm init

This command will create a package.json file. You will get prompts to provide the following information:

  • package-name: As you learned earlier in this tutorial, the name of your package must be unique. Also it must be lowercase. It may include hyphens.

  • version: The initial value is 1.0.0. You update the number when you update your package using semantic versioning.

  • description: You can provide a description of your package here. Indicate what your package does and how to use it.

  • entry point: The entry file for your code. The default value is index.js.

  • test command: Here, you can add the command you want to run when a user runs npm run test.

  • git repository: The link to your remote repository on GitHub.

  • keywords: Add relevant keywords that will help others find your package on the NPM registry.

  • author: Add your name.

  • license: You can add a license or use the default license (Internet Systems Consortium (ISC) License).

4. Add Your Code

Now, you can go ahead and add the code for your package.

First, you need to create the file that will be loaded when your module is required by another application. For this tutorial, that will be the index.js file.

Inside the index.js file, add the code for your package.

For this tutorial, I will be creating a simple package called ss-first-package . This package returns the string "Hello Master!".

//index.js

function SayHello(){
    return "Hello Master!";
}

module.exports = SayHello

After creating your function, you should export it

How to Test Your NPM Package

Testing ensures that your NPM package works as expected. There are many ways to test your package. In this tutorial, you will learn one of the simplest ways of testing.

First, navigate to the root of your package project. Then, run the following command:

npm link

This will make your package available globally. And you can require the package in a different project to test it out.

Create a test folder. And inside that test folder, add a script.js file.

To add the package you created to your test folder, run the command below:

npm link <name-of-package>

npm link ss-first-package

This will create a node-modules folder. And it'll add all the files and folders from your package – see the screenshot below:

In the script.js file, you can now require your package and use it for the test.

The ss-first-package package is expected to return the string "Hello Master!". As you can see from the screenshot below, the package works as expected when I run the script.

After testing your package and ensuring it works as expected, you can now publish it on the NPM registry.

How to Publish Your NPM Package

To publish your package on the NPM registry, you need to have an account. If you don't have an account, visit the NPM sign up page to create one.

After creating the account, open your terminal and run the following command in the root of your package:

npm login

You will get a prompt to enter your username and password. If login is successful, you should see a message like this:

Logged in as <your-username> on <https://registry.npmjs.org/.\>

You can now run the following command to publish your package on the NPM registry:

npm publish

If you have been following along, then congratulations! You just published your first NPM package.

You can visit the NPM website and run a search for your package. You should see your package show up in the search results.

For example, from the screenshot below, you can see the ss-first-package package is now available on NPM.

The ss-first-package, package is now available on NPM