external setValue : Dom.element -> string -> unit = "value" [@@bs.set]

external setTextContent : Dom.element -> string -> unit = "textContent"
  [@@bs.set]

external setStyle : Dom.element -> string -> unit = "style" [@@bs.set]

external setClassName : Dom.element -> string -> unit = "className" [@@bs.set]

external setAttribute : Dom.element -> string -> string -> unit = "setAttribute"
  [@@bs.send]

external setAttributeNS : Dom.element -> string -> string -> string -> unit
  = "setAttributeNS"
  [@@bs.send]

external addEventListener : Dom.element -> string -> (Dom.event -> unit) -> unit
  = "addEventListener"
  [@@bs.send]

external appendChild : Dom.element -> Dom.element -> unit = "appendChild"
  [@@bs.send]

external firstChild : Dom.element -> Dom.element Js.Nullable.t = "firstChild"
  [@@bs.get]

external removeChild : Dom.element -> Dom.element -> unit = "removeChild"
  [@@bs.send]

let removeFirstChild element =
  match Js.toOption (firstChild element) with
  | Some child ->
      let () = removeChild element child in
      true
  | _ -> false

let rec removeChildren element =
  if removeFirstChild element then removeChildren element else ()

let mountOn base element =
  let () = removeChildren base in
  appendChild base element