yarn

Install all dependencies from package.json

$ yarn install

$ yarn add [package]

$ yarn add --dev [package]

$ yarn remove [package]

$ yarn upgrade

$ yarn run [script]

$ yarn init

$ yarn upgrade-interactive

yarn [command] [flags]

Yarn is a fast, reliable, and secure dependency manager for JavaScript. It caches every package it downloads, enabling offline installation of previously fetched packages. Yarn parallelizes operations for faster performance compared to npm.
Running yarn with no command executes yarn install. Running yarn script executes a user-defined script from package.json. The lockfile yarn.lock ensures consistent installations across machines.
Yarn 2+ (Berry) introduces Plug'n'Play for zero-install workflows and improved workspace support. Configuration can be set globally or per-project via .yarnrc.yml.

install

Install all dependencies from package.json.

Add a package to project dependencies.

Remove a package from the project.

Upgrade packages to their latest version based on version range.

Execute a script defined in package.json.

Initialize a new project, creating package.json.

Publish a package to a registry.

Create a new project from a starter kit.

Manage Yarn configuration settings.

Clean the global cache.

Add package as a dev dependency.

Install package globally.

Print verbose output for the command.

Specify a working directory.

Ensure only one Yarn instance runs (file or network).

Display help for a command.

Display version information.

Two major versions exist: Yarn Classic (1.x) and Yarn Modern (2+/Berry) with different features and configurations. Yarn Modern uses Plug'n'Play by default, which may require project configuration adjustments. The global install location differs from npm.

Yarn was developed by Facebook (now Meta) in collaboration with Exponent, Google, and Tilde, and released in October 2016 as an alternative to npm. It addressed npm's performance and security issues at the time. Yarn 2 (Berry), a complete rewrite, was released in January 2020 with features like Plug'n'Play and improved workspaces. Yarn is now a community-driven project.

npm(1), pnpm(1), node(1), npx(1)