Defining how to declare our dependencies

[maledr5]

This discussion is to follow up on our conversation around bundling and to help us define a common understanding on how to use dependencies in our packages.

Let's discuss

Please add your comments on which scenarios you consider we use a dependency as a devDependency, Dependency or PeerDependency

For example:
My understanding of peerDependencies is ...
I think we should use this dep as a peerDependency because ...
We should not use this dep as a dependency because ...

Based on this we can write a guide on how to move forward.

Some Initial Context

Yarn Definitions

The following are literal definitions taken from yarn

dependencies

These are your normal dependencies, or rather ones that you need when running your code (e.g. React or ImmutableJS).

devDependencies

These are your development dependencies. Dependencies that you need at some point in the development workflow but not while running your code (e.g. Babel or Flow).

peerDependencies

Peer dependencies are a special type of dependency that would only ever come up if you were publishing your own package.

Having a peer dependency means that your package needs a dependency that is the same exact dependency as the person installing your package. This is useful for packages like react that need to have a single copy of react-dom that is also used by the person installing it.

From node blog

npm versions 1, 2, and 7 will automatically install peerDependencies if they are not explicitly depended upon higher in the dependency tree.

peerDependenciesMeta

From npm

When a user installs your package, npm will emit warnings if packages specified in peerDependencies are not already installed. The peerDependenciesMeta field serves to provide npm more information on how your peer dependencies are to be used. Specifically, it allows peer dependencies to be marked as optional.

Other information

peerDependencies seem to have been created to use for plugins.
Please follow up our Including Lit as a dependency discussion for more context on how each of this impact our project.