To get an idea on how to deal with ZIP files in code:
— in C, minimal-style library: https://github.com/richgel999/miniz, look especially at https://github.com/richgel999/miniz/blob/master/miniz_zip.h
— in JS, writing only and no compression: https://github.com/PaulCapron/pwa2uwp/blob/master/src/zip.js (255 lines including blanks & comments)