Adding a comment to code that needs clarification.
Improving existing unit tests and adding a few more for exercisesService validation.
Fixing a bug by passing the right type in to a function.

None of the exercise reps for a day were showing up because a function expecting a certain object only got a number. Typescript would have helped here, in the future that should probably be used.
Adding in a local copy of require.js.

Just linking to it from their site is a bad idea, it's not a CDN and that location can go down and take down the site.
Adding unit tests for repMaxes.