How to not encode nil field from Struct using Jason

Background

I have a TypedStruct with an optional field, :rank. This field is sometimes present and sometimes not.

  @derive Jason.Encoder
  typedstruct enforce: true do
    @typedoc "An order."

    field(:item_id, String.t())
    field(:rank, non_neg_integer(), enforce: false)
  end

The ideal situation here would be to generate the struct without the field, should the :rank parameter be missing. However, since I am dealing with structs, this is not possible, so I have to contempt with the nil value representing the absence of :rank.

The problem here is that when I use Jason.encode(...) , I am going to get a "rank": null in the result json object. I really don’t want this.

Question

Is there an option in Jason that allows me to not encode nil values, other than manually implementing the Encode Protocol myself?