let format_float precision f =
  let str = Js.Float.toString f in
  match Js.String.split "." str with
    | [| a ; b |] -> a ^ "." ^ (Js.String.substring ~from:0 ~to_:precision b)
    | _ -> str

external btoa : string -> string = "btoa"
  [@@bs.val] [@@bs.scope "window"]

external atob : string -> string = "atob"
  [@@bs.val] [@@bs.scope "window"]

external unescape : string -> string = "unescape"
  [@@bs.val]

external escape : string -> string = "escape"
  [@@bs.val]

external encodeURIComponent : string -> string = "encodeURIComponent"
  [@@bs.val]

external decodeURIComponent : string -> string = "decodeURIComponent"
  [@@bs.val]

let encode str =
  str
    |> encodeURIComponent
    |> unescape
    |> btoa

let decode str =
  str
    |> atob
    |> escape
    |> decodeURIComponent