Do I need outlets in a built-in bookshelf?
I read the 2017 code (clause 210.52(A)(2)(1)) as such:


  ... a wall space shall include ... any space 2ft or more in width and ... unbroken along the floor line by ... fixed cabinets that do not have countertops or similar work surfaces.


This says to me that walls on either side are to be treated separately, not that the cabinet requires outlets as though it was wall space. Therefore, you aren't required to fit outlets into your cabinet.