extract the "users" branch from the database via streaming

bash

jq -nc --stream '
   def atomize(s):
     fromstream(foreach s as $in ( {previous:null, emit: null};
       if ($in | length == 2) and ($in|.[0][0]) != .previous and .previous != null
       then {emit: [[.previous]], previous: $in|.[0][0]}
       else { previous: ($in|.[0][0]), emit: null}
       end;
       (.emit // empty), $in) ) ;
   atomize(1|truncate_stream(inputs | select(.[0][0] == "users")))' fb_yamm_data.json > yamm_users.json