diff --git a/src/Core__JSON.mjs b/src/Core__JSON.mjs
index e6a8e3a7..e26011ca 100644
--- a/src/Core__JSON.mjs
+++ b/src/Core__JSON.mjs
@@ -1,5 +1,6 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
+import * as Caml_option from "rescript/lib/es6/caml_option.js";
 
 function classify(value) {
   var match = Object.prototype.toString.call(value);
@@ -34,14 +35,66 @@ function classify(value) {
   }
 }
 
-var Decode = {
+var Classify = {
   classify: classify
 };
 
 var Encode = {};
 
+function bool(json) {
+  if (typeof json === "boolean") {
+    return json;
+  }
+  
+}
+
+function $$null(json) {
+  if (json === null) {
+    return null;
+  }
+  
+}
+
+function string(json) {
+  if (typeof json === "string") {
+    return json;
+  }
+  
+}
+
+function $$float(json) {
+  if (typeof json === "number") {
+    return json;
+  }
+  
+}
+
+function object(json) {
+  if (typeof json === "object" && !Array.isArray(json) && json !== null) {
+    return Caml_option.some(json);
+  }
+  
+}
+
+function array(json) {
+  if (Array.isArray(json)) {
+    return json;
+  }
+  
+}
+
+var Decode = {
+  bool: bool,
+  $$null: $$null,
+  string: string,
+  $$float: $$float,
+  object: object,
+  array: array
+};
+
 export {
-  Decode ,
+  Classify ,
   Encode ,
+  Decode ,
 }
 /* No side effect */
diff --git a/src/Core__JSON.res b/src/Core__JSON.res
index 7df41e44..100ae5ee 100644
--- a/src/Core__JSON.res
+++ b/src/Core__JSON.res
@@ -23,7 +23,7 @@ external stringifyAnyWithReplacer: ('a, jsonReplacer) => option<string> = "JSON.
 external stringifyAnyWithReplacerAndIndent: ('a, jsonReplacer, int) => option<string> =
   "JSON.stringify"
 
-module Decode = {
+module Classify = {
   type t =
     | Bool(bool)
     | Null
@@ -60,3 +60,24 @@ module Encode = {
   external object: Core__Dict.t<t> => t = "%identity"
   external array: array<t> => t = "%identity"
 }
+
+module Decode = {
+  let bool = (json: t) =>
+    Core__Type.typeof(json) === #boolean ? Some((Obj.magic(json): bool)) : None
+  let null = (json: t) => Obj.magic(json) === Core__Null.null ? Some(Core__Null.null) : None
+  let string = (json: t) =>
+    Core__Type.typeof(json) === #string ? Some((Obj.magic(json): string)) : None
+  let float = (json: t) =>
+    Core__Type.typeof(json) === #number ? Some((Obj.magic(json): float)) : None
+  let object = (json: t) =>
+    if (
+      Core__Type.typeof(json) === #object &&
+      !Core__Array.isArray(json) &&
+      !(Obj.magic(json) === Core__Null.null)
+    ) {
+      Some((Obj.magic(json): Core__Dict.t<t>))
+    } else {
+      None
+    }
+  let array = (json: t) => Core__Array.isArray(json) ? Some((Obj.magic(json): array<t>)) : None
+}
diff --git a/src/Core__JSON.resi b/src/Core__JSON.resi
new file mode 100644
index 00000000..fc086a01
--- /dev/null
+++ b/src/Core__JSON.resi
@@ -0,0 +1,55 @@
+type t = Js.Json.t
+
+type jsonReviver
+external asJsonReviver: 'a => jsonReviver = "%identity"
+type jsonReplacer
+external asJsonReplacer: 'a => jsonReplacer = "%identity"
+
+@val external parseExn: string => t = "JSON.parse"
+@val external parseExnWithReviver: (string, jsonReviver) => t = "JSON.parse"
+@val external stringify: t => string = "JSON.stringify"
+@val external stringifyWithIndent: (t, @as(json`null`) _, int) => string = "JSON.stringify"
+@val external stringifyWithReplacer: (t, jsonReplacer) => string = "JSON.stringify"
+@val external stringifyWithReplacerAndIndent: (t, jsonReplacer, int) => string = "JSON.stringify"
+
+@val external parseToAnyExn: string => 'a = "JSON.parse"
+@val external parseToAnyExnWithReviver: (string, jsonReviver) => 'a = "JSON.parse"
+@val external stringifyAny: 'a => option<string> = "JSON.stringify"
+@val
+external stringifyAnyWithIndent: ('a, @as(json`null`) _, int) => option<string> = "JSON.stringify"
+@val
+external stringifyAnyWithReplacer: ('a, jsonReplacer) => option<string> = "JSON.stringify"
+@val
+external stringifyAnyWithReplacerAndIndent: ('a, jsonReplacer, int) => option<string> =
+  "JSON.stringify"
+
+module Classify: {
+  type t =
+    | Bool(bool)
+    | Null
+    | String(string)
+    | Number(float)
+    | Object(Core__Dict.t<t>)
+    | Array(array<t>)
+
+  let classify: 'a => t
+}
+
+module Encode: {
+  external bool: bool => t = "%identity"
+  external null: t = "#null"
+  external string: string => t = "%identity"
+  external int: int => t = "%identity"
+  external float: float => t = "%identity"
+  external object: Core__Dict.t<t> => t = "%identity"
+  external array: array<t> => t = "%identity"
+}
+
+module Decode: {
+  let bool: t => option<bool>
+  let null: t => option<Core__Null.t<'a>>
+  let string: t => option<string>
+  let float: t => option<float>
+  let object: t => option<Core__Dict.t<t>>
+  let array: t => option<array<t>>
+}
diff --git a/src/Core__Null.res b/src/Core__Null.res
index dc6e2fb5..2b9c0c9e 100644
--- a/src/Core__Null.res
+++ b/src/Core__Null.res
@@ -2,7 +2,7 @@ type t<'a> = Js.Null.t<'a>
 
 external asNullable: t<'a> => Core__Nullable.t<'a> = "%identity"
 
-external empty: t<'a> = "#null"
+external null: t<'a> = "#null"
 
 external make: 'a => t<'a> = "%identity"
 
@@ -11,5 +11,5 @@ external toOption: t<'a> => option<'a> = "#null_to_opt"
 let fromOption: option<'a> => t<'a> = option =>
   switch option {
   | Some(x) => make(x)
-  | None => empty
+  | None => null
   }
diff --git a/src/Core__Nullable.res b/src/Core__Nullable.res
index 2f3e9a2d..044a037b 100644
--- a/src/Core__Nullable.res
+++ b/src/Core__Nullable.res
@@ -4,8 +4,6 @@ external null: t<'a> = "#null"
 
 external undefined: t<'a> = "#undefined"
 
-external empty: t<'a> = "#undefined"
-
 external make: 'a => t<'a> = "%identity"
 
 external toOption: t<'a> => option<'a> = "#nullable_to_opt"
@@ -13,5 +11,5 @@ external toOption: t<'a> => option<'a> = "#nullable_to_opt"
 let fromOption: option<'a> => t<'a> = option =>
   switch option {
   | Some(x) => make(x)
-  | None => empty
+  | None => undefined
   }
diff --git a/src/RescriptCore.mjs b/src/RescriptCore.mjs
index dbccf7a7..281e3abb 100644
--- a/src/RescriptCore.mjs
+++ b/src/RescriptCore.mjs
@@ -15,8 +15,6 @@ var $$Error;
 
 var Float;
 
-var Global;
-
 var Int;
 
 var $$BigInt;
@@ -107,7 +105,6 @@ export {
   Dict ,
   $$Error ,
   Float ,
-  Global ,
   Int ,
   $$BigInt ,
   $$Math ,
diff --git a/test/TempTests.mjs b/test/TempTests.mjs
index 21d3ae2c..e26239c0 100644
--- a/test/TempTests.mjs
+++ b/test/TempTests.mjs
@@ -118,14 +118,14 @@ console.info("---");
 
 var json = JSON.parse("{\"foo\": \"bar\"}");
 
-var json$1 = Core__JSON.Decode.classify(json);
+var json$1 = Core__JSON.Classify.classify(json);
 
 var tmp;
 
 if (typeof json$1 === "number" || json$1.TAG !== /* Object */3) {
   tmp = undefined;
 } else {
-  var value = Core__JSON.Decode.classify(json$1._0["foo"]);
+  var value = Core__JSON.Classify.classify(json$1._0["foo"]);
   tmp = typeof value === "number" || value.TAG !== /* String */1 ? undefined : value._0;
 }
 
diff --git a/test/TempTests.res b/test/TempTests.res
index f936a283..b300526a 100644
--- a/test/TempTests.res
+++ b/test/TempTests.res
@@ -57,9 +57,9 @@ Console.info("JSON")
 Console.info("---")
 let json = JSON.parseExn(`{"foo": "bar"}`)
 Console.log(
-  switch JSON.Decode.classify(json) {
+  switch JSON.Classify.classify(json) {
   | Object(json) =>
-    switch JSON.Decode.classify(json->Dict.get("foo")) {
+    switch JSON.Classify.classify(json->Dict.get("foo")) {
     | String(value) => Some(value)
     | _ => None
     }