how-to-add-a-dependency-to-a-cs-package.md

Add a dependency to a SharedComponents package

• To add an other package from the mono-repo to your package (package names are specified in package.json files):

  yarn lerna add --scope=<my-package> <package-to-add>
  yarn

• To add an external dependency:

  • Add it directly to the package.json file of the SharedComponents package
  • Run yarn at the root of the SharedComponents.

ℹ️ yarn add <dependency> or yarn upgrade <dependency> inside a SharedComponents package folder has known issues and shouldn't be used for now. The SharedComponents team is working towards correcting these issues.

How to choose between dependencies, devDependencies and peerDependencies?

Why should you care ? : You can read this article to understand why it is not a good thing to only use dependencies.

Let's assume there is a foo package in SharedComponents, and it needs some functions from the bar package (which is external).

1. If your host project has bar as dependency, put bar as a peerDependency of foo. Test locally on your Host project with a yarn link. This will probably fail hard in case of a problem.
2. If your project does not have bar, add it in the dependencies of foo.

• If the dependency is only used for development (ex: flow, jest), don't forget to add it to the devDependencies instead

• If the dependency is exposed as part of the package interface, such as React, then you need to add it as a peerDependencies. To know when to add a package as a peer dependency, you can refer to this article. A warning will be printed if someone installs the SharedComponents package on a project on which the peer dependency is not installed.