`yarn`

Getting Started

What is `yarn`?

yarn is a more secure node package manager, developed by facebook. It has some cool features, like using parallel processing to install packages, and caching packages on your local machine to prevent needless re-downloading.

Installing `yarn`

# on macOS
brew install yarn

# on Debian distro
# curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
# echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
# sudo apt update
# sudo apt install yarn
sudo apt install yarnpkg
sudo update-alternatives --install /usr/bin/yarn yarn /usr/bin/yarnpkg 1
echo "export NODE_PATH=/usr/lib/nodejs:/usr/share/nodejs" >> ~/.zshrc

Upgrading `yarn`

brew upgrade yarn
apt upgrade yarnpkg

Using `yarn`

Configurations

You can use $ yarn config set to declare configurations that will be used when creating a new project with $ yarn init

yarn config set init-license MIT
yarn config set name 'Austin Traver'

You can check what a current configurations using $ yarn config get

yarn config get init-license

You can remove a configuration with $ yarn config delete <keyname>

yarn config delete init-license

Starting a new project

mkdir project
cd project
yarn init

Joining an existing project

If you have just downloaded someone’s repository, and it already includes a package.json file, type yarn install inside the repository to download all of the packages for this project

Managing project dependencies

# [Install package to local project]
yarn add packagename
# [Install package globally to computer]
yarn global add create-react-app
# [Upgrade all existing dependencies]
yarn upgrade
# [Remove a dependency no longer needed]
yarn remove
# [Install all current project dependencies]
yarn install

What is `yarn.lock`?

The yarn.lock file stores the exact version number of all of the dependencies for your project. Do not modify it.

Misc

Storing user credentials

yarn login

This will allow you to store your user credentials for the node package registry. Before this will work, you must first create an account on npmjs.com

Finding out where `yarn` is installed

yarn global bin

This will return the location that yarn is located. If you installed yarn with brew then it will return /usr/local/bin

Getting the version number of a dependency

yarn info mypackage version

Publishing Yarn Packages

yarn login
yarn --registry
yarn publish <folder>

You'll need to create a package.json in the directory you're hosting the project in. It will need to include the dependencies, a name, a version number, and description.

You'll need to supply a bin field in your package.json so that yarn and npm can add the binary executable to the $PATH when the user installs the package globally.

{
  "name": "merge",
  "version": "1.0.1",
  "bin":
}

Custom Installation Location

By default, $ yarn global add <package> installs a symlink to the package, and stores that symlink in /usr/local/bin/<package> but you can customize this with $ yarn config set prefix

Set yarn global package directory

Add symlinks to globally added packages in ~/.yarn/bin/<package>

yarn config set prefix ~/.yarn

Check yarn global package directory

You can use the $ yarn global bin command to see where symlinks for globally added packages are. By default, this is /usr/local/bin

yarn global bin

Check where the node packages are actually installed

yarn by default houses global node modules in ~/.config/yarn/global

yarn global dir

Switch from Node to Yarn

If you have a project that was previously using a package-lock.json file, but you want to switch from npm to yarn, there is now a way to do that. Yarn is able to parse that file and generate an equivalent yarn.lock file. From there, you will be able to use yarn add instead of npm install.

yarn import

yarn