let concat xs ys =
  let partition_class =
    Js.Array.reduce
      (fun (class_acc, rest_acc) z ->
        match z with
        | H.TextAttr ("class", c) -> (class_acc ^ " " ^ c, rest_acc)
        | _ -> (class_acc, Js.Array.concat [| z |] rest_acc)
      )
      ("", [| |])
  in
  let (xs_class, xs_rest) = partition_class xs in
  let (ys_class, ys_rest) = partition_class ys in
  let rest = Js.Array.concat xs_rest ys_rest in
  if xs_class == "" && ys_class == "" then
    rest
  else
    Js.Array.concat [| H.TextAttr ("class", xs_class ^ " " ^ ys_class) |] rest

(* Attribute creation *)

let id v = H.TextAttr ("id", v)

let class_ v = H.TextAttr ("class", v)

let viewBox v = H.TextAttr ("viewBox", v)

let d v = H.TextAttr ("d", v)

let type_ v = H.TextAttr ("type", v)

let min_ v = H.TextAttr ("min", v)

let value v = H.TextAttr ("value", v)

let for_ v = H.TextAttr ("for", v)

let style v = H.TextAttr ("style", v)

let href v = H.TextAttr ("href", v)

let autocomplete v = H.TextAttr ("autocomplete", v)

let download v = H.TextAttr ("download", v)