Module Jsoo_weak_collections.Weak_map

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap

type ('a, 'b) t
val create : unit -> ('a, 'b) t
val set : ('a, 'b) t -> 'a -> 'b -> unit
val get : ('a, 'b) t -> 'a -> 'b option
val delete : ('a, 'b) t -> 'a -> unit