Idiomatic way to create a variable spring data mongodb Query in Kotlin?

Question

Using Kotlin and spring data mongodb, I'm trying to find the most idiomatic method that can receive nullable parameters (through user defined filters) and create a MongoTemplate Query with the non-null ones (which, in Java, would be a bunch of ifs). This is what I came up with, so far, but I wonder if there's a better way:

// extending Query
open class Filter {
  // case insensitive 'like' criteria
  fun Query.like(field: String, value: String?) = value?.let {
    this.addCriteria(Criteria.where(field).regex(it,"i"))
  }

  // queries from a date, to a date or between two dates
  fun <T: Comparable<T>> Query.between(field: String, from: T?, to: T?) {
    if (from != null || to != null) {
      val criteria = where(field)
      from?.let { criteria.gte(it) }
      to?.let { criteria.lte(it) }
      this.addCriteria(criteria)
    }
  }

  fun Query.onlyActive(active: Boolean?) = when (active) {
    true -> this.addCriteria(Criteria.where("active").`is`(true))
    else -> null
  }
}

// data class extending Filter()
data class myFilter(val: name: String, val type: String?, val content:String?,
  val fromNum: Int?, val toNum: Int?, val fromDate: LocalDateTime?,
  val toDate: LocalDateTime?, val active? = false): Filter() {

  fun toQuery(): Query {
    // name is a mandatory param
    val query = Query.query(Criteria.where("name").`is`(name))

    with(query) {
      like("type", type)
      like("content", content)
      between("num", fromNum, toNum)
      between("date", fromDate, toDate)
      onlyActive(active)
    }

    return query
  }
}