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.
sig type ('a, 'b, 'c) t val create : ('a, 'b) Bigarray.kind -> 'c Bigarray.layout -> int -> int -> int -> ('a, 'b, 'c) Bigarray.Array3.t external dim1 : ('a, 'b, 'c) Bigarray.Array3.t -> int = "%caml_ba_dim_1" external dim2 : ('a, 'b, 'c) Bigarray.Array3.t -> int = "%caml_ba_dim_2" external dim3 : ('a, 'b, 'c) Bigarray.Array3.t -> int = "%caml_ba_dim_3" external kind : ('a, 'b, 'c) Bigarray.Array3.t -> ('a, 'b) Bigarray.kind = "caml_ba_kind" external layout : ('a, 'b, 'c) Bigarray.Array3.t -> 'c Bigarray.layout = "caml_ba_layout" external get : ('a, 'b, 'c) Bigarray.Array3.t -> int -> int -> int -> 'a = "%caml_ba_ref_3" external set : ('a, 'b, 'c) Bigarray.Array3.t -> int -> int -> int -> 'a -> unit = "%caml_ba_set_3" external sub_left : ('a, 'b, Bigarray.c_layout) Bigarray.Array3.t -> int -> int -> ('a, 'b, Bigarray.c_layout) Bigarray.Array3.t = "caml_ba_sub" external sub_right : ('a, 'b, Bigarray.fortran_layout) Bigarray.Array3.t -> int -> int -> ('a, 'b, Bigarray.fortran_layout) Bigarray.Array3.t = "caml_ba_sub" val slice_left_1 : ('a, 'b, Bigarray.c_layout) Bigarray.Array3.t -> int -> int -> ('a, 'b, Bigarray.c_layout) Bigarray.Array1.t val slice_right_1 : ('a, 'b, Bigarray.fortran_layout) Bigarray.Array3.t -> int -> int -> ('a, 'b, Bigarray.fortran_layout) Bigarray.Array1.t val slice_left_2 : ('a, 'b, Bigarray.c_layout) Bigarray.Array3.t -> int -> ('a, 'b, Bigarray.c_layout) Bigarray.Array2.t val slice_right_2 : ('a, 'b, Bigarray.fortran_layout) Bigarray.Array3.t -> int -> ('a, 'b, Bigarray.fortran_layout) Bigarray.Array2.t external blit : ('a, 'b, 'c) Bigarray.Array3.t -> ('a, 'b, 'c) Bigarray.Array3.t -> unit = "caml_ba_blit" external fill : ('a, 'b, 'c) Bigarray.Array3.t -> 'a -> unit = "caml_ba_fill" val of_array : ('a, 'b) Bigarray.kind -> 'c Bigarray.layout -> 'a array array array -> ('a, 'b, 'c) Bigarray.Array3.t val map_file : Unix.file_descr -> ?pos:int64 -> ('a, 'b) Bigarray.kind -> 'c Bigarray.layout -> bool -> int -> int -> int -> ('a, 'b, 'c) Bigarray.Array3.t external unsafe_get : ('a, 'b, 'c) Bigarray.Array3.t -> int -> int -> int -> 'a = "%caml_ba_unsafe_ref_3" external unsafe_set : ('a, 'b, 'c) Bigarray.Array3.t -> int -> int -> int -> 'a -> unit = "%caml_ba_unsafe_set_3" end