time_difference.dart

final yesterday = DateTime(now.year, now.month, now.day); // today 12.00.00
final tomorrow = DateTime(now.year, now.month, now.day +1); //tomorrow 12.00.00

int diffInDays = tomorrow.difference(yesterday).inDays;
if (diffInDays == 0){
    //custom code
    print( "same day");
} else if( diffInDays > 0 ) {
    // custom code
    print("tomorrow is greater ");
} else{
    // custom code
    print(" yesterday is less" );
}