How to handle array data type?

[sandgupta23]

{
  fname: "john",
  lname: "doe"
  interest_id: [1,2,3,4,5,6]
}

field can only be used for primitive data (fname and lname) but is there anything to handle array data (interest_id)

[dlamon1]

Is this not the general use case form inputs, they are strings only afaik