TypeError: groups is not iterable

[mcndt]

On query:

list 
past 2 weeks
include projects "Reading"
group by date
sort desc

The group by expression causes the following console error and an infinite loading spinner:

Note that the query only includes a single project.

Solution:

1. Resolve bug
2. Make future exceptions bubble up to the Svelte component such that it can display an error message instead of infinite loading.