flatten Json to arrays and primitive types

JsonFlatten.fs

open Newtonsoft.Json
    let rec private _flattenJson (delim:string) (pkey:string) (json:JsonValue): (string * JsonValue) seq =
        json.Properties
        |> Seq.collect (fun (k, v) ->
            match v with
            | JsonValue.Record r -> _flattenJson delim k (JsonValue.Record r)
            | _ -> [(pkey + delim + k, v)] |> Seq.ofList
        )

    /// flatten a Json nested children and stop at primitive or Array. specify delimiter for nested key names.
    let flattenJson delimiter (json: JsonValue) =
        _flattenJson delimiter "" json
        |> Seq.map (fun (k, v) -> k, v.ToString())