Creating project-specific ESLint rules in a Yarn workspace

I recently needed to figure out how to create custom project-specific lint rules for a repository that is using Yarn workspaces where ESLint is run from the workspace root.

• Create an ESLint plugin as a private (”private”: true in its package.json) in the workspace (parallel with other packages) and define the ESLint rules there.

• Add a dependency on that package to your workspace’s root package.json using the link:<path> syntax. Mine looked like: "eslint-plugin-relay-internal": "link:./packages/eslint-plugin-relay-internal",

• Reference the package normally in the workspace’s eslintrc.

You can see the PR here: https://github.com/facebook/relay/pull/4147