[MUSIC]

Hello, I'm Andrew, and welcome to this workshop where we'll take a look

at how to build and distribute a package with npm.

Npm is a package manager both for the browser and

server side JavaScript projects.

If you're unfamiliar with the basic usage of npm,

you should check out our npm basics course linked in the teacher's notes.

Npm is used by companies and

open source developers to distribute their code for others to use.

Companies distribute nodes modules to interact with their API.

And developers create and

distribute utilities or packages that they think may be useful for others.

If you have JavaScript code that you want to share with other JavaScript developers,

you can use npm to distribute it.

Whilst there is nothing stopping you from publishing any JavaScript code to npm,

the only reason you should be publishing a package is for

other people to use as a dependency.

Like a node module or a command line utility.

In fact, more and

more developers are using npm as a way to distribute their JavaScript projects.

For example,

j query recommends that developers distribute their tokens via npm.

Also, check the npm code of conduct for package restrictions and more guidelines.

To distribute a package on npm,

firstly you've got to create an account with the npm website.

It's free and you just need to supply your email address.

Next, you open up a a command line till like the command prompt on Windows or

the terminal on a Mac on your local machine.

And use the login command on npm to login.

We need to make sure that we have a package.json file

with all the correct information filled in.

To make sure that our package .json file is correct,

we can test that it is by locally installing the package that we've created.

Once we're happy that the package runs correctly, we can publish it.

Let's take a look at the process on my local machine.

If you want to look at this curtain and follow along.

You can download the files under the download tab on this page.

However, don't publish this same code.

I've already published it on npm.

On the other hand, if you have your own JavaScript package and

you want to publish that, then follow along with your own code, and

then publish it to the npm repository.

The package I want to distribute provides a simple way to retrieve the latest

information about posts being published on the Treehouse blog.

I have a blog.js file which includes all the coding for this package.

There's a readme file that contains the basic usage of the package, and finally

there's a gitignore file making sure that we don't check in the node modules folder.

This is the get, you don't want to be checking this in.

Npm ignores the node modules folder anyway when you publish your package.

My programming depends on another package, libxmljs,

libxmljs needs to be compiled on the local machine running the package.

This is another reason why you don't want to check in your node modules folder.

It may run a care on the Mac OS 10 operating system, but

it won't run on a Linux machine.

Each different operating system requires you to compile for that given system.

Running npm install will trigger the installation and

compilation of any dependencies for that system.

Here I am on the npmjs.com website, the official site for npm.

You need to login to the site before you can upload your package to

npm central repository.

Complete this form with your information, but be mindful down here.

Your email will be shown with all packages that you publish.

This is so that if there's an issue with your package, someone can contact you and

give you the details of the issues that they're having.

Once you're done filling in this form, submit it and follow any additional steps.

Now that you're signed up on the npm site, we can login or

authenticate in the command line application npm.

When you login to npm in the command line,

it opens up new features like the ability to publish a package.

I'm in the project folder right now, and

the most important part of an npm package is the package.json file.

Let's create it using the npm init command.

Values in brackets are default values that npm guesses.

Treehouse_blog seems like a sensible name.

Version one?

Sure.

Description?

I'm going to lift that from the README file.

The entry point is the main file of your package.

This is the file that you'd want to include in a separate project

that has all functionality in, blog.js is the right file.

There are no tests.

You shouldn't really be publishing software with no tests, but

this is basic enough to get away with it.

I can add tests later on.

I can add my github reaper for this project.

And then there's the keywords for this project.

This is to help the npm search facility.

Treehouse, blog, rss and json make sense.

Author, Andrew Chalkley.

And finally the license.

It's impossible for people who are using your software to know how they can use it.

I'm going to use the MIT license because that's what's popular with FrailMax and

libraries like J Query and Rebiemwells.

This looks good.

And that's the hard bit over when you create the package.jsn file,

you're basically getting your package ready for distribution.

Let's see if we've got everything set up correctly before publishing.

I am going to go one folder up.

And create a new directory called package_test.

This is where I am going to test that the package is working correctly.

Let's create a file example.js.

And then, copy and paste the basic usage from the README into the example.js.

Now to install the package in the project folder.

Npm install has a usage where you can install from a folder.

Just type, npm install.

And then the path to your

package.

As you can see there's a node_modules folder now with treehouse_blog installed.

Let's type node example .js, and

see if it prints out the latest blog articles with the information.

Yes, and it does.

Finally, let's go back to our treehouse_blog folder.

We can now use the npm's publish command.

And that's it.

We can go to npmjs.com now and search for treehouse_blog.

And there it is.

Now anyone can install this npm package by using npm install treehouse_blog.

With your projects don't forget to commit this source code to GitHub so

others can see it and contribute to your project.

And if there are any issues they can file them there.