Yarn

Common Commands

yarn install               # install dependencies from package.json
yarn add <package>           # add a dependency
yarn add -D <package>          # add a dev dependency
yarn remove <package>            # remove a dependency
yarn up <package>                  # upgrade a dependency
yarn run <script>                    # run a package.json script
yarn <script>                          # shorthand for `yarn run <script>`
yarn why <package>                       # explain why a package is installed

Workspaces Basics

package.json at the repo root:

{
  "private": true,
  "workspaces": ["packages/*"]
}

yarn workspaces list                          # list all workspaces
yarn workspace <name> add <package>             # add a dependency to one workspace
yarn workspace <name> run <script>                # run a script in one workspace
yarn workspaces foreach run build                   # run a script in every workspace

• Workspaces let a single install manage multiple packages in one repo, hoisting shared dependencies to the root node_modules.

Comparison Notes with npm

Common Flags

yarn install --immutable          # fail if the lockfile would change (CI)
yarn add <package>@<version>        # install a specific version
yarn add <package> --peer             # add as a peer dependency
yarn install --check-cache              # verify the local cache is valid

References

• Yarn Documentation
• Yarn CLI Commands
• Yarn Workspaces