Answers for "set failed: value argument contains an invalid key ($key) in property 'shopping-cards.-MchUSNJJuczbp8aNDTG.items.-MbLJBAhawE-98MJy0_F.product'. Keys must be non-empty strings and can't contain ".", "#", "$", "/", "[", or "]""

set failed: value argument contains an invalid key ($key) in property 'shopping-cards.-MchUSNJJuczbp8aNDTG.items.-MbLJBAhawE-98MJy0_F.product'. Keys must be non-empty strings and can't contain ".", "#", "$", "/", "[", or "]"

DONT Use simblos like $, #,"," "...., etc in your KEYs, in your Interfaces. Neither nor in your OBJECT that will set or update the db. !