Union.Unsafe
val get_a : ('a Js_of_ocaml.Js.t, _) t Js_of_ocaml.Js.t -> 'a Js_of_ocaml.Js.t
val get_b : (_, 'b Js_of_ocaml.Js.t) t Js_of_ocaml.Js.t -> 'b Js_of_ocaml.Js.t