TodoMVC throws if item is edited and saved as empty

[seanastephens]

To reproduce:

1. Create a todo item
2. Double-click to edit it
3. Delete all of its text
4. Press enter.

There is an exception on the console, but more concretely the double-click to edit feature is broken.

The stack points to here:

          (todo, editingId) => todo.id === editingId,

and I suspect this is due to some interaction between actions.destroy and the function there -- maybe combine runs the function when editingId$ updates (not sure though).

It would be nice to be able to write that function without having to null check the arguments, but I'm not sure yet where that fix goes.

[brandonpayton]

Thanks for logging this! I'll take a look when I next have time.

By the way, I took some time to write out what I'd like to see for the next iteration and plan to create issues for everything this weekend.