Yarn 2 & Yarn Plug'n'Play
In 2020 the Yarn team released a major update, Yarn 2.0, also codenamed "Berry". This version came with a full rewriting of both the codebase (which migrated to TypeScript in the process) and test suite. Many features were introduced, a cleaving one being a new unique installation strategy called Yarn Plug'n'Play. Under this default but optional mode, Yarn wouldn't generate anode_modules
folder anymore, instead opting to generate a single Node.js resolver file named .pnp.cjs
. While justified by the Yarn team as a need to address multiple design flaws in the typical Node.js module resolution, this change required some support from other projects in the ecosystem which took some time to materialise, adding friction to the migration from Yarn 1.22. to Yarn 2.0.
Plugins
Users can write their own plugins for Yarn.Constraints
Yarn constraints allow users to enforce rules for their dependencies or manifest fields across scoped workspaces.Offline cache
Downloaded packages are cached and stored as a single file.Plug'n'Play
Plug'n'Play allows users to run Node projects withoutnode_modules
folder, defining the way or location to resolve dependencies package files with the Plug-n-Play-control file. This feature is aimed to fix an unwell structured node_modules
architecture and resulting in a faster Node.js application start-up time.
Plugins
Plugins can add new resolvers, fetchers, linkers, commands, and can also register to some events or be integrated with each other, most features of Yarn are implemented through plugins, includingyarn add
and yarn install
, which are also preinstalled plugins.
Protocols
Users can define which protocol will be used to resolve certain packages, for example, the ''git'' protocol is used for downloading a public package from a Git repository, and the ''patch'' protocol is used for creating a patched copy of the original package.Release Workflow
Release Workflow automatically upgrades relative packages amongWorkspaces
Workspaces allow multiple projects to work together in the same repository and automatically apply changes to other relatives when source code is modified, allowing installation of multiple packages in a single pass by running the installation command only once.Zero-Installs
Zero-Installs solve the needs of installation of packages when packages is required to install when the codes is just fresh fetched to local.Comparison to npm
* Yarn can install packages from local cache. * Yarn binds versions of the package strongly. * Yarn uses checksum for ensuring data integrity, while npm uses SHA-512 to check data integrity of the packages downloaded. * Yarn installs packages in parallel, while npm installs one package at a time.Syntax
To install yarn: npm install -g yarn To install a package with yarn: yarn add package-name To install a package with yarn for development and testing purposes: yarn add package-name --dev NB: in the first versions, it was: yarn install package-name --save-devSee also
* npm * Node.js *References
External links
* {{Official website JavaScript programming tools Free package management systems Free software programmed in TypeScript Free software programmed in JavaScript Software using the BSD license