Make compare order independent, add equal and tests.

To make the comparison order-independent, sort the keys before comparing them.

Author: Cristiano Calcagno

jscomp/runtime/caml_obj.ml

@@ -138,6 +138,8 @@ module O = struct
   type key = Obj.t
   external keys : Obj.t -> keys = "Object.keys" [@@bs.val]
   external length : keys -> int = "%array_length"
+  external sort : unit -> unit [@bs.meth] = "" [@@bs.val]
+  let sort (keys:keys) : unit = (Obj.magic keys)##sort ()
   external get_key : keys -> int -> key = "%array_unsafe_get"
   external get_value : Obj.t -> key -> Obj.t = "%array_unsafe_get"
 end
@@ -212,6 +214,8 @@ let rec caml_compare (a : Obj.t) (b : Obj.t) : int =
             begin
               let keys_a = O.keys a in
               let keys_b = O.keys b in
+              O.sort(keys_a);
+              O.sort(keys_b);
               let len_a = O.length keys_a in
               let len_b = O.length keys_b in
               let min_len = min len_a len_b in
@@ -298,6 +302,18 @@ let rec caml_equal (a : Obj.t) (b : Obj.t) : bool =
         else
           let len_a = Bs_obj.length a in
           let len_b = Bs_obj.length b in
+          if len_a = 0 && len_b = 0 && O.is_object a && O.is_object b then
+            begin
+              let keys_a = O.keys a in
+              let keys_b = O.keys b in
+              let len_a = O.length keys_a in
+              let len_b = O.length keys_b in
+              len_a = len_b &&
+              let () = O.sort(keys_a) in
+              let () = O.sort(keys_b) in
+              aux_obj_equal a keys_a b keys_b 0 len_a
+            end
+        else
           if len_a = len_b then
             aux_equal_length a b 0 len_a
           else false
@@ -307,7 +323,14 @@ and aux_equal_length  (a : Obj.t) (b : Obj.t) i same_length =
   else
     caml_equal (Obj.field a i) (Obj.field b i)
     && aux_equal_length  a b (i + 1) same_length
-
+and aux_obj_equal (a: Obj.t) keys_a (b: Obj.t) keys_b i length =
+  if i = length then true
+  else
+    let key_a = O.get_key keys_a i in
+    let key_b = O.get_key keys_b i in
+    caml_equal key_a key_b &&
+    caml_equal (O.get_value a key_a) (O.get_value b key_b) &&
+    aux_obj_equal a keys_a b keys_b (i+1) length
 
 let caml_equal_null (x : Obj.t) (y : Obj.t Js.null) = 
   match Js.nullToOption y with