The Method GetPlayerBans should return:
SteamId (string)
CommunityBanned (bool)
VACBanned (bool)
NumberOfVACBans (int)
DaysSinceLastBan (int)
NumberOfGameBans (int)
EconomyBan (string)
like in: https://developer.valvesoftware.com/wiki/Steam_Web_API#GetPlayerBans_.28v1.29
Your Method just returnes:
steamId: '',
communityBanned: ,
VACBanned: ,
numberOfVACBans: ,
daysSinceLastBan: ,
economyBan: ''
So without NumberOfGameBans it is not Possible to find out if the Player is banned since today, cause then it says 0 daysSinceLastBan.