Js.MapBindings to functions in Map
ES6 Map API
val make : unit -> ('k, 'v) tval fromArray : ('k * 'v) array -> ('k, 'v) tval toArray : ('k, 'v) t -> ('k * 'v) arrayval size : ('k, 'v) t -> intval has : ('k, 'v) t -> key:'k -> boolval get : ('k, 'v) t -> key:'k -> 'v optionval clear : ('k, 'v) t -> unitval delete : ('k, 'v) t -> key:'k -> boolval keys : ('k, 'v) t -> 'k Js.iteratorval values : ('k, 'v) t -> 'v Js.iteratorval entries : ('k, 'v) t -> ('k * 'v) Js.iterator