Add JSDoc to existing tested files.

[cogwizzle]

Add JSDoc
As a developer working with the files in the project it would be nice to have type safety for the things that are already tested.

Acceptance Criteria
All files that have a corresponding test will also have JSDoc describing the internals of the files.

Describe the solution you'd like
Inventory the files and create stories for the files that already have test written for them.

Describe alternatives you've considered
Adding all the JSDoc at once is possible, but would not likely be good practice for keeping track of what is going on.

Additional context
This work is tech debt.