Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!
If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.
module MakeSeeded: functor (H : SeededHashedType) -> SeededS  with type key = H.tHashtbl.MakeSeeded returns a structure containing
    a type key of keys and a type 'a t of hash tables
    associating data of type 'a to keys of type key.
    The operations perform similarly to those of the generic
    interface, but use the seeded hashing and equality functions
    specified in the functor argument H instead of generic
    equality and hashing.  The create operation of the
    result structure supports the ~random optional parameter
    and returns randomized hash tables if ~random:true is passed
    or if randomization is globally on (see Hashtbl.randomize).| Parameters: | 
 | 
type key 
type 'a t 
val create : ?random:bool -> int -> 'a t
val clear : 'a t -> unit
val reset : 'a t -> unit
val copy : 'a t -> 'a t
val add : 'a t -> key -> 'a -> unit
val remove : 'a t -> key -> unit
val find : 'a t -> key -> 'a
val find_all : 'a t -> key -> 'a list
val replace : 'a t -> key -> 'a -> unit
val mem : 'a t -> key -> bool
val iter : (key -> 'a -> unit) -> 'a t -> unit
val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
val length : 'a t -> int
val stats : 'a t -> Hashtbl.statistics