baloneysandwiches/parse-srcset — pull request #6 by aFarkas (2014-12-14 20:32:51+00:00)
Title: 1x normalization and has1x or hasW flag

Although this is not a direct part of the srcset parsing logic, it would help to do some normalization:

1. Normalize no descriptor to "1x"
2. If a srcset uses x descriptors (has no w descriptor), but has no 1x descriptor declared, the normal src attribute should be added to the list of candidates (as 1x).