Yarn is a tool for managing, updating, and sharing your Java code. Yarn works through node.js helping to track libraries, dependencies, and even enables you to share solutions with other developers.
In this tutorial learn how to install Yarn on Ubuntu 18.04.
- A user account with sudo privileges
- Access to a terminal window / command line (Ctrl-Alt-T)
Option 1: Install Yarn Using Ubuntu Repositories
Yarn developers maintain a repository for installing directly to Ubuntu that simplifies the installation process. For detailed inustrctions, follow the steps below.
Step 1: Configure the Yarn Repository
Open a terminal window, and add the GPG key:
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
The GPG key ensures that you’re installing authentic software. Next, add the Yarn repository:
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
This adds the Yarn repository to your master repository list.
Now, your standard package manager can access and manage Yarn.
Step 2: Install Yarn
Update your local repository listings:
sudo apt-get update
sudo apt-get install yarn
This command installs Yarn on your system. If you don’t already have node.js installed, your package manager will install it for you.
To verify a successful installation, display the Yarn version:
Option 2: Install Yarn Using NPM
1. Start by listing the version to check if NPM in installed:
If you don’t have npm, install it by running the following command:
sudo apt install npm
2. To install Yarn with npm:
sudo npm install yarn –g
Upon installing, the output should notify you which version of Yarn has been installed. In the example above, it is version 1.17.3.
In many ways, Yarn is very similar to npm. Yarn adds a yarn.lock file, which restricts packages to a specific version. This is especially helpful for maintaining a consistent development environment.
How to Upgrade Yarn Version
To upgrade Yarn to the latest version, run the following command from the terminal:
curl --compressed -o- -L https://yarnpkg.com/install.sh | bash
The system will download the Yarn tarball and install the latest version. The image below displays the output you can expect.
Basic Yarn Usage
Now that you have Yarn installed, the sections below dive into how to use basic Yarn commands.
Create a New Yarn Project
To create a new project, enter the following:
yarn init my_project
The system will launch a script that will ask questions about the project. Press enter to use the default for each entry.
Add a Dependency to Your Project
A package (sometimes called a module) is a self-contained piece of code. It holds all the components needed to run or work on the code. A package may rely on other packages. These are called dependencies, because the package needs them to function.
To Install a dependency, enter the following:
yarn add <em>insert_package_name</em>
The command above adds the latest version of the named package.
To install a specific version, enter the following:
yarn add <em>insert_package_name</em>@<em>version</em>
If the package has a tag, simply substitute [version] for [tag]:
yarn add <em>insert_package_name</em>@<em>tag</em>
This process automatically updates the package.json file. It also updates the yarn.lock file. This ensures that everyone using the package is working with the same software.
Upgrade a Yarn Dependency
To upgrade a dependency, use the command:
yarn upgrade <em>insert_package_name</em>
Like the add command, Yarn can be upgraded by version or tag:
yarn upgrade <em>insert_package_name</em>@<em>version</em>
yarn upgrade <em>insert_package_name</em>@<em>tag</em>
Remove a Yarn Dependency
Remove a dependency by entering the command:
yarn remove <em>insert_package_name</em>
Install Additional Dependencies
Yarn works through the package.json configuration file. This file keeps a record of all the packages required for your project. When you’re working on a code project, you may add a package that has additional dependencies.
To install these dependencies, enter the following:
This will update and load all the dependencies for your project configuration.
Yarn is set up to allow multiple users, and to control versions. In some cases, a different developer may add a package to the master package.json file. If that’s the case, you should run the yarn install command as soon as possible. This will update your version of the project, and ensure that you’re working in the same environment.
You should now have a good understanding of how to install Yarn on an Ubuntu system. We also covered basic commands for working with Yarn projects.