Consume private libraries from GitHub Packages using npm or yarn

The first time I tried consuming a private JavaScript library from the GitHub Packages Registry, I had to navigate through a handful of webpages and wrangle a bunch of information together before I was able to run a simple npm or yarn install. That’s why I’m excited to put all the information you need in a simple-to-follow article. Please note that this article assumes you’re running an unix operating system.

Here’s an overview of the steps we’re covering:

  1. Create a personal access token on GitHub
  2. Add an npm registry resolver to your local environment
  3. Add a file to the repository that will be consuming the private package
  4. Start consuming your packages

Before we can start consuming private packages, the registry needs to know who you are each time you try to access it. That’s why we’ll start by creating a personal access token on GitHub. Your system will use it each time it needs to access the GitHub Packages Registry to install libraries.

Create a personal access token on GitHub

Start by creating a personal token on GitHub:

  1. For the Note field, put down “GitHub Packages” as the description, so we’ll know what we used this token for in the future
  2. Under Select scopes, select the repo option: (checking the repo scope, should automatically check all the options under it:)

    • repo:status
    • repo_deployment
    • public_repo
    • repo:invite
    • security_events
    • read:packages
  3. Hit the “Generate Token” button
  4. Copy the newly generated token onto your clipboard, as we’re going to use it shortly

Add an npm registry resolver to your local environment

We’re going to authenticate you into the GitHub Packages Registry by using your GitHub username and the Personal Access Token you just created as the password. To do so, pull up your Terminal and follow these steps:

  • Run npm login --registry=https://npm.pkg.github.com and enter these options:

    • Username: Enter your GitHub username
    • Password: Paste the Personal Access Token you previously created
    • Email: Enter an email address associated with your GitHub account

Now npm will know how to forward your authentication credentials to the GitHub Packages Registry every time we try to access it. That way GitHub Packages will know who you are and what packages you have access to.

Configure package consumption

Let’s create a new file at the root of your project called .npmrc. This file will instruct npm (or yarn) to pull packages directly from the GitHub Packages Registry. Below is an example of what your file should look like:

# File location: `~/some-directory/your-project/.npmrc`
# Registry for the @my-org scope
@my-org:registry=https://npm.pkg.github.com/

Now any libraries you add via npm or yarn that use the @my-org scope will be installed directly from the GitHub Packages Registry.

A little background on package scopes

The GitHub Packages Registry requires library authors to follow a few conventions when publishing packages. Understanding those conventions will add some color to how we’re configuring your development environment.

When publishing a package to the GitHub Packages Registry, package names must live under a package scope. If you’re interested in examples of scoped JavaScript packages, you need to look no further than Angular projects. If you look at any projects that use Angular, you’ll notice that the names of the dependencies that Angular brings in have a scope (aka namespace, or a vendor prefix) of @angular, such as @angular/core, or @angular/router.

The scope that library authors must use can be either their GitHub usernames, or their GitHub organization’s name, such as @sergiocruz/library-name, or @my-org/library-name.

Global npm configuration instead of project-level configuration

It’s my personal preference to configure package consumption by project, thereby adding an .npmrc file to each of my projects that will consume private libraries from the GitHub Packages Registry.

I prefer project-level configuration over a global npm configuration for the same reasons why I prefer to use scoped variables instead of global variables when writing JavaScript. Some folks coined this concept as the Strictness Principle: Restrict the scope of what you do. Increase the scope as the need arises. I feel similarly about configuration, it’s easier to spot mistakes when they’re scoped to a single project. It is possible, however, to configure npm globally to consume scoped packages from the GitHub Packages Registry, if that’s what you prefer to do.

You should already have an npm configuration file under your user’s home directory, namely ~/.npmrc. Add the same lines mentioned above for the per-project configuration:

# File location: ~/.npmrc
# Registry for the @my-org scope
@my-org:registry=https://npm.pkg.github.com/

Now every time you install any packages under the @my-org scope anywhere on your machine, npm will know to fetch those packages from the GitHub Packages Registry.

Start consuming your packages

After configuring your work environment, you’ll be able to follow the same steps you usually do to install any packages.

Pull up your terminal and run:

npm install @my-org/package-name --save

If you prefer to use yarn, all the previous steps we followed should work seamlessly for it.

yarn add @my-org/package-name

If you’d like a deeper dive into GitHub Packages, I would suggest browsing through their documentation to learn more about how to configure npm for use with GitHub Packages, among other use cases.

I hope this a helpful resource as you get a good handle on how to consume private npm libraries using GitHub Packages. Please feel free to reach out to me, preferrably via Twitter, if you think this guide is missing any key information.

Sergio Cruz

Copyright © 2020 Sergio Cruz. All rights reserved.