[ 'name', 'surname' ] - will import those fields as-is
[ 'full_name' => 'name', 'day_of_birth' => ['dob', 'type'=>'date'] ] - use alias and options
[ ['dob', 'type' => 'date'] ] - use options
You may also use second param to specify parameters:
addFields(['from', 'to'], ['type' => 'date']);