Yarn manages your dependencies, but who manages the package manager? That’s the role of Yarn Switch.

Distributed as a separate binary with each Yarn release, Yarn Switch is a binary that substitutes to the actual Yarn binary and ensures that your team always uses the correct version of Yarn for the active project.

Here’s what happens when you call your yarn binary:

1. Yarn Switch (~/.yarn/switch/bin/yarn) gets called.
2. It searches for the nearest package.json file containing a packageManager field.
3. It checks whether the project is configured for Yarn, and returns an error if not.
4. It then checks whether the requested version is available locally. If not, it downloads it.
5. It executes the cached binary, passing along any CLI arguments you provided.

Note

Yarn Switch is very similar in idea to Corepack, except it’s officially maintained by the Yarn team and is designed specifically for Yarn.

Given that the Node.js TSC decided to phase out Corepack into Node.js, we decided to refocus our efforts on Yarn and now recommend using Yarn Switch over Corepack when possible.

Where are the binaries downloaded from?

Yarn Switch downloads the binaries from the official website. Your network administrators may need to allowlist the repo.yarnpkg.com domain for the endpoints to be available.

We don’t offer proxy settings at the moment, but contributions to this effect are welcome.

Configuring Yarn Switch for Docker images

As you won’t want to rely on our endpoints for your runtime images, you should make sure to populate your images at build time with the Yarn version your project will need to run. You usually will face one of those two scenarios:

You run your container as root

RUN curl -s https://repo.yarnpkg.com/install | bash
ENV PATH="/root/.yarn/switch/bin:$PATH"
RUN yarn switch cache --install

Your runtime user is different from the build user

RUN curl -s https://repo.yarnpkg.com/install | bash
RUN mv ~/.yarn/switch/bin/yarn /usr/local/bin/yarn

USER node

RUN yarn switch cache --install

How to upgrade the Yarn version in a project?

Run yarn set version latest and Yarn will bump the packageManager field in your package.json file.

Are the binaries signed?

The binaries aren’t signed at the moment, but we’re working on it and hope to have that set up before Yarn 6 reaches a stable release.