BuckleScript FFI cheatsheet

NOTE: The translations given here might not be literally correct. The output will in some instances have been simplified slightly to improve clarity.

Basic

(* ml *)
external f : 'a -> 'b -> 'ret = "" [@@bs.val]

let ret = f a b

// js
var ret = f(a, b);

(* ml *)
external f : 'self -> 'ret = "" [@@bs.get]

let ret = f self

// js
var ret = self.f;

(* ml *)
external f : 'self -> 'a -> 'ret = "" [@@bs.set]

let ret = f self a

// js
var ret = self.f = a;

(* ml *)
external f : 'self -> 'a -> 'b -> 'ret = "" [@@bs.send]

let ret = f self a b

// js
var ret = self.f(a, b);

(* ml *)
external f : 'a -> 'b -> 'ret = "" [@@bs.send.pipe: 'self]

let ret = f a b self
(* or *)
let ret = self |> f a b

// js
var ret = self.f(a, b);

(* ml *)
external f : unit -> 'ret = "" [@@bs.new]

let ret = f ()

// js
var ret = new f();

(* ml *)
external f : unit -> unit = "" [@@bs.module "m"]

let _ = f ()

// js
var m = require('m');
m.f();

(* ml *)
external f : 'self -> 'key -> 'ret = "" [@@bs.get_index]

let ret = f self key

// js
var ret = self[key];

(* ml *)
external f : 'self -> 'key -> 'a -> 'ret = "" [@@bs.set_index]

let ret = f self key a

// js
var ret = self[key] = a;

(* ml *)
external f : 'a -> 'b array -> 'ret = "" [@@bs.val] [@@bs.splice]

let ret = f a [|b1; b2; b3|]

// js
var ret = f(a, b1, b2, b3);

(* ml *)
external f : unit -> unit = "" [@@bs.val] [@@bs.scope "a", "b"]

let _ = f ()

// js
a.b.f();

(* ml *)
external f : 'a -> _ [@bs.as "b"] -> 'c -> unit = "" [@@bs.val]

let _ = f a c

// js
f(a, "b", c);

(* ml *)
external f : ([`a] [@bs.string]) -> unit = "" [@@bs.val]

let _ = f `a

// js
f("a");

(* ml *)
external f : ([`a] [@bs.int]) -> unit = "" [@@bs.val]

let _ = f `a

// js
f(0);

(* ml *)
external f : ([`int of int] [@bs.unwrap]) -> unit = "" [@@bs.val]

let _ = f (`int 42)

// js
f(42);

(* ml *)
external f : 'a -> 'b [@bs.ignore] -> 'c -> unit = "" [@@bs.val]

let _ = f a b c

// js
f(a, c);

(* ml *)
let re = [%re "/na/gi"]

// js
var re = /na/gi;

(* ml *)
let obj = [%obj { property = "value" }]

// js
var obj = {
  property: "value"
};

(* ml *)
let raw = [%raw "1 + 2 == 3"]

// js
var raw = (1 + 2 == 3);

(* ml *)
[%debugger]

// js
debugger;