Some small tidies to view.js

[georgestephanis]

Correcting one property snag where it's getting left when it seems like it should be right, as well as handling an error case where the css value to be converted is false-y (null, or empty string) -- that happened to me in some local testing and was an important addition.

[georgestephanis]

I didn't include building in the PR intentionally, in case it's easier to merge this with other changes and build them all together, to avoid conflicts.