diff --git a/jscomp/gentype_tests/typescript-react-example/Makefile b/jscomp/gentype_tests/typescript-react-example/Makefile
index e1f64bccb5..2794f18826 100644
--- a/jscomp/gentype_tests/typescript-react-example/Makefile
+++ b/jscomp/gentype_tests/typescript-react-example/Makefile
@@ -5,6 +5,9 @@ test:
 	npm run build
 	npm run tsc
 	npm run lint
+	@git diff --quiet src/ \
+		|| { echo; echo "Please review the Gentype outputs too!"; echo; false; } \
+		|| exit 1
 
 clean:
 	rm -rf node_modules lib src/*.res.js src/*.gen.tsx
diff --git a/jscomp/gentype_tests/typescript-react-example/package-lock.json b/jscomp/gentype_tests/typescript-react-example/package-lock.json
index 5fdd739d29..f98e37ff32 100644
--- a/jscomp/gentype_tests/typescript-react-example/package-lock.json
+++ b/jscomp/gentype_tests/typescript-react-example/package-lock.json
@@ -24,14 +24,15 @@
     },
     "../../..": {
       "name": "rescript",
-      "version": "11.1.0",
+      "version": "12.0.0-alpha.1",
       "dev": true,
       "hasInstallScript": true,
       "license": "SEE LICENSE IN LICENSE",
       "bin": {
         "bsc": "bsc",
         "bstracing": "lib/bstracing",
-        "rescript": "rescript"
+        "rescript": "rescript",
+        "rewatch": "scripts/rewatch"
       },
       "devDependencies": {
         "mocha": "10.1.0",
@@ -39,7 +40,7 @@
         "prettier": "2.7.1"
       },
       "engines": {
-        "node": ">=10"
+        "node": ">=18"
       }
     },
     "node_modules/@aashutoshrathi/word-wrap": {
diff --git a/jscomp/gentype_tests/typescript-react-example/src/BucklescriptAnnotations.res.js b/jscomp/gentype_tests/typescript-react-example/src/BucklescriptAnnotations.res.js
index 7f66df862d..711ea7d6dd 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/BucklescriptAnnotations.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/BucklescriptAnnotations.res.js
@@ -2,11 +2,11 @@
 
 
 function bar(x) {
-  var f = x.twoArgs;
+  let f = x.twoArgs;
   return f(3, "a");
 }
 
 export {
-  bar ,
+  bar,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Comments.res.js b/jscomp/gentype_tests/typescript-react-example/src/Comments.res.js
index 2575585401..91c8819bc8 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Comments.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Comments.res.js
@@ -5,11 +5,11 @@ function _placeholder(run, times) {
   
 }
 
-var DecideSubject = {
+let DecideSubject = {
   _placeholder: _placeholder
 };
 
 export {
-  DecideSubject ,
+  DecideSubject,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Core.res.js b/jscomp/gentype_tests/typescript-react-example/src/Core.res.js
index 0864298fc2..b967c504e0 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Core.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Core.res.js
@@ -98,36 +98,36 @@ function someFunWithNullUndefinedArg(prim0, prim1) {
   return CoreGen.someFunWithNullUndefinedArg(prim0, prim1);
 }
 
-var $$Map;
+let $$Map;
 
-var $$Set;
+let $$Set;
 
 export {
-  null0 ,
-  null1 ,
-  nullable0 ,
-  nullable1 ,
-  undefined0 ,
-  undefined1 ,
-  dict0 ,
-  dict1 ,
-  promise0 ,
-  promise1 ,
-  date0 ,
-  date1 ,
-  bigint0 ,
-  bigint1 ,
-  regexp0 ,
-  regexp1 ,
-  $$Map ,
-  $$Set ,
-  map1 ,
-  weakmap1 ,
-  set1 ,
-  weakset1 ,
-  option0 ,
-  option1 ,
-  someFunWithNullThenOptionalArgs ,
-  someFunWithNullUndefinedArg ,
+  null0,
+  null1,
+  nullable0,
+  nullable1,
+  undefined0,
+  undefined1,
+  dict0,
+  dict1,
+  promise0,
+  promise1,
+  date0,
+  date1,
+  bigint0,
+  bigint1,
+  regexp0,
+  regexp1,
+  $$Map,
+  $$Set,
+  map1,
+  weakmap1,
+  set1,
+  weakset1,
+  option0,
+  option1,
+  someFunWithNullThenOptionalArgs,
+  someFunWithNullUndefinedArg,
 }
 /* ./Core.gen Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler1.res.js b/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler1.res.js
index 858279113e..3ab09d2586 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler1.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler1.res.js
@@ -5,21 +5,21 @@ import * as ErrorHandler from "./ErrorHandler.res.js";
 
 function notification(s) {
   return [
-          s,
-          s
-        ];
+    s,
+    s
+  ];
 }
 
-var Error1 = {
+let Error1 = {
   notification: notification
 };
 
-var MyErrorHandler = ErrorHandler.Make(Error1);
+let MyErrorHandler = ErrorHandler.Make(Error1);
 
 Curry._1(MyErrorHandler.notify, "abc");
 
 export {
-  Error1 ,
-  MyErrorHandler ,
+  Error1,
+  MyErrorHandler,
 }
 /* MyErrorHandler Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler2.res.js b/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler2.res.js
index ef8547fe5f..3789d0aeda 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler2.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/CreateErrorHandler2.res.js
@@ -4,19 +4,19 @@ import * as ErrorHandler from "./ErrorHandler.res.js";
 
 function notification(n) {
   return [
-          String(n),
-          ""
-        ];
+    String(n),
+    ""
+  ];
 }
 
-var Error2 = {
+let Error2 = {
   notification: notification
 };
 
-var MyErrorHandler = ErrorHandler.Make(Error2);
+let MyErrorHandler = ErrorHandler.Make(Error2);
 
 export {
-  Error2 ,
-  MyErrorHandler ,
+  Error2,
+  MyErrorHandler,
 }
 /* MyErrorHandler Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Derivings.res.js b/jscomp/gentype_tests/typescript-react-example/src/Derivings.res.js
index 5165501116..ff4db0087c 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Derivings.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Derivings.res.js
@@ -3,18 +3,18 @@
 
 function submit(param_0) {
   return {
-          TAG: "Submit",
-          _0: param_0
-        };
+    TAG: "Submit",
+    _0: param_0
+  };
 }
 
-var click = "Click";
+let click = "Click";
 
-var cancel = "Cancel";
+let cancel = "Cancel";
 
 export {
-  click ,
-  submit ,
-  cancel ,
+  click,
+  submit,
+  cancel,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Docstrings.res.js b/jscomp/gentype_tests/typescript-react-example/src/Docstrings.res.js
index 2ab5a33b9d..b8306b2910 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Docstrings.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Docstrings.res.js
@@ -73,27 +73,27 @@ function unitArgWithConversionU() {
   return "A";
 }
 
-var flat = 34;
+let flat = 34;
 
 export {
-  flat ,
-  signMessage ,
-  one ,
-  two ,
-  tree ,
-  oneU ,
-  twoU ,
-  treeU ,
-  useParam ,
-  useParamU ,
-  unnamed1 ,
-  unnamed1U ,
-  unnamed2 ,
-  unnamed2U ,
-  grouped ,
-  unitArgWithoutConversion ,
-  unitArgWithoutConversionU ,
-  unitArgWithConversion ,
-  unitArgWithConversionU ,
+  flat,
+  signMessage,
+  one,
+  two,
+  tree,
+  oneU,
+  twoU,
+  treeU,
+  useParam,
+  useParamU,
+  unnamed1,
+  unnamed1U,
+  unnamed2,
+  unnamed2U,
+  grouped,
+  unitArgWithoutConversion,
+  unitArgWithoutConversionU,
+  unitArgWithConversion,
+  unitArgWithConversionU,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/DynamicallyLoadedComponent.res.js b/jscomp/gentype_tests/typescript-react-example/src/DynamicallyLoadedComponent.res.js
index 9eb45eebb7..2c1b3e2173 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/DynamicallyLoadedComponent.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/DynamicallyLoadedComponent.res.js
@@ -5,9 +5,9 @@ function DynamicallyLoadedComponent(Props) {
   return Props.s;
 }
 
-var make = DynamicallyLoadedComponent;
+let make = DynamicallyLoadedComponent;
 
 export {
-  make ,
+  make,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/EmitModuleIfNoConversion.res.js b/jscomp/gentype_tests/typescript-react-example/src/EmitModuleIfNoConversion.res.js
index f73e0e7ede..b21c04a379 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/EmitModuleIfNoConversion.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/EmitModuleIfNoConversion.res.js
@@ -4,22 +4,22 @@
 function foo(t) {
   if (typeof t !== "object") {
     console.log("A");
-    return ;
+    return;
   }
   console.log("B" + t.name);
 }
 
-var X = {
+let X = {
   foo: foo,
   x: 42
 };
 
-var Y = {
+let Y = {
   x: ""
 };
 
 export {
-  X ,
-  Y ,
+  X,
+  Y,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ErrorHandler.res.js b/jscomp/gentype_tests/typescript-react-example/src/ErrorHandler.res.js
index 27dcce45a2..78be0122f9 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ErrorHandler.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ErrorHandler.res.js
@@ -3,18 +3,18 @@
 import * as Curry from "rescript/lib/es6/curry.js";
 
 function Make($$Error) {
-  var notify = function (x) {
+  let notify = function (x) {
     return Curry._1($$Error.notification, x);
   };
   return {
-          notify: notify
-        };
+    notify: notify
+  };
 }
 
-var x = 42;
+let x = 42;
 
 export {
-  Make ,
-  x ,
+  Make,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ExportWithRename.res.js b/jscomp/gentype_tests/typescript-react-example/src/ExportWithRename.res.js
index 41537fe199..27c42e8666 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ExportWithRename.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ExportWithRename.res.js
@@ -5,9 +5,9 @@ function ExportWithRename(Props) {
   return Props.s;
 }
 
-var make = ExportWithRename;
+let make = ExportWithRename;
 
 export {
-  make ,
+  make,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/FirstClassModules.res.js b/jscomp/gentype_tests/typescript-react-example/src/FirstClassModules.res.js
index f5e1e861fb..1fabb0dd1b 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/FirstClassModules.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/FirstClassModules.res.js
@@ -1,11 +1,11 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var y = "abc";
+let y = "abc";
 
-var EmptyInnerModule = {};
+let EmptyInnerModule = {};
 
-var InnerModule2 = {
+let InnerModule2 = {
   k: 4242
 };
 
@@ -13,18 +13,18 @@ function k3(x) {
   return x + 1 | 0;
 }
 
-var InnerModule3 = {
+let InnerModule3 = {
   k3: k3
 };
 
-var Z = {
+let Z = {
   u: [
     0,
     0
   ]
 };
 
-var M = {
+let M = {
   y: y,
   EmptyInnerModule: EmptyInnerModule,
   InnerModule2: InnerModule2,
@@ -33,7 +33,7 @@ var M = {
   x: 42
 };
 
-var firstClassModule = {
+let firstClassModule = {
   x: 42,
   EmptyInnerModule: EmptyInnerModule,
   InnerModule2: InnerModule2,
@@ -48,21 +48,21 @@ function testConvert(m) {
 
 function SomeFunctor(X) {
   return {
-          ww: X.y
-        };
+    ww: X.y
+  };
 }
 
 function someFunctorAsFunction(x) {
   return {
-          ww: x.y
-        };
+    ww: x.y
+  };
 }
 
 export {
-  M ,
-  firstClassModule ,
-  testConvert ,
-  SomeFunctor ,
-  someFunctorAsFunction ,
+  M,
+  firstClassModule,
+  testConvert,
+  SomeFunctor,
+  someFunctorAsFunction,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/FirstClassModulesInterface.res.js b/jscomp/gentype_tests/typescript-react-example/src/FirstClassModulesInterface.res.js
index 6d7febd4ad..6b29d6830a 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/FirstClassModulesInterface.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/FirstClassModulesInterface.res.js
@@ -1,12 +1,12 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var r = {
+let r = {
   x: 3,
   y: "hello"
 };
 
 export {
-  r ,
+  r,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Hooks.res.js b/jscomp/gentype_tests/typescript-react-example/src/Hooks.res.js
index cd15d84f9d..15fa6d069c 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Hooks.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Hooks.res.js
@@ -6,84 +6,84 @@ import * as ImportHooks from "./ImportHooks.res.js";
 import * as ImportHookDefault from "./ImportHookDefault.res.js";
 
 function Hooks(Props) {
-  var vehicle = Props.vehicle;
-  var match = React.useState(function (param) {
-        return 0;
-      });
-  var setCount = match[1];
-  var count = match[0];
+  let vehicle = Props.vehicle;
+  let match = React.useState(function (param) {
+    return 0;
+  });
+  let setCount = match[1];
+  let count = match[0];
   return React.createElement("div", undefined, React.createElement("p", undefined, "Hooks example " + (vehicle.name + (" clicked " + (String(count) + " times")))), React.createElement("button", {
-                  onClick: (function (param) {
-                      Curry._1(setCount, (function (param) {
-                              return count + 1 | 0;
-                            }));
-                    })
-                }, "Click me"), React.createElement(ImportHooks.make, {
-                  person: {
-                    name: "Mary",
-                    age: 71
-                  },
-                  children: null,
-                  renderMe: (function (x) {
-                      return x.randomString;
-                    })
-                }, "child1", "child2"), React.createElement(ImportHookDefault.make, {
-                  person: {
-                    name: "DefaultImport",
-                    age: 42
-                  },
-                  children: null,
-                  renderMe: (function (x) {
-                      return x.randomString;
-                    })
-                }, "child1", "child2"));
+    onClick: (function (param) {
+      Curry._1(setCount, (function (param) {
+        return count + 1 | 0;
+      }));
+    })
+  }, "Click me"), React.createElement(ImportHooks.make, {
+    person: {
+      name: "Mary",
+      age: 71
+    },
+    children: null,
+    renderMe: (function (x) {
+      return x.randomString;
+    })
+  }, "child1", "child2"), React.createElement(ImportHookDefault.make, {
+    person: {
+      name: "DefaultImport",
+      age: 42
+    },
+    children: null,
+    renderMe: (function (x) {
+      return x.randomString;
+    })
+  }, "child1", "child2"));
 }
 
 function Hooks$Another$anotherComponent(Props) {
-  var vehicle = Props.vehicle;
-  var callback = Props.callback;
+  let vehicle = Props.vehicle;
+  let callback = Props.callback;
   Curry._1(callback, undefined);
   return React.createElement("div", undefined, "Another Hook " + vehicle.name);
 }
 
-var Another = {
+let Another = {
   anotherComponent: Hooks$Another$anotherComponent
 };
 
 function Hooks$Inner(Props) {
-  var vehicle = Props.vehicle;
+  let vehicle = Props.vehicle;
   return React.createElement("div", undefined, "Another Hook " + vehicle.name);
 }
 
 function Hooks$Inner$Another$anotherComponent(Props) {
-  var vehicle = Props.vehicle;
+  let vehicle = Props.vehicle;
   return React.createElement("div", undefined, "Another Hook " + vehicle.name);
 }
 
-var Another$1 = {
+let Another$1 = {
   anotherComponent: Hooks$Inner$Another$anotherComponent
 };
 
 function Hooks$Inner$Inner2(Props) {
-  var vehicle = Props.vehicle;
+  let vehicle = Props.vehicle;
   return React.createElement("div", undefined, "Another Hook " + vehicle.name);
 }
 
 function Hooks$Inner$Inner2$Another$anotherComponent(Props) {
-  var vehicle = Props.vehicle;
+  let vehicle = Props.vehicle;
   return React.createElement("div", undefined, "Another Hook " + vehicle.name);
 }
 
-var Another$2 = {
+let Another$2 = {
   anotherComponent: Hooks$Inner$Inner2$Another$anotherComponent
 };
 
-var Inner2 = {
+let Inner2 = {
   make: Hooks$Inner$Inner2,
   Another: Another$2
 };
 
-var Inner = {
+let Inner = {
   make: Hooks$Inner,
   Another: Another$1,
   Inner2: Inner2
@@ -93,7 +93,7 @@ function Hooks$NoProps(Props) {
   return React.createElement("div", undefined, null);
 }
 
-var NoProps = {
+let NoProps = {
   make: Hooks$NoProps
 };
 
@@ -103,14 +103,14 @@ function functionWithRenamedArgs(_to, _Type, cb) {
 }
 
 function Hooks$WithRename$componentWithRenamedArgs(Props) {
-  var _to = Props._to;
-  var _Type = Props._Type;
-  var cb = Props.cb;
+  let _to = Props._to;
+  let _Type = Props._Type;
+  let cb = Props.cb;
   Curry._1(cb, _to);
   return _to.name + _Type.name;
 }
 
-var WithRename = {
+let WithRename = {
   componentWithRenamedArgs: Hooks$WithRename$componentWithRenamedArgs
 };
 
@@ -120,8 +120,8 @@ function makeWithRef(vehicle) {
       return null;
     } else {
       return React.createElement("button", {
-                  ref: ref
-                }, vehicle.name);
+        ref: ref
+      }, vehicle.name);
     }
   };
 }
@@ -130,31 +130,31 @@ function Hooks$WithRef$makeWithRef(Props) {
   return makeWithRef(Props.vehicle);
 }
 
-var WithRef = {
+let WithRef = {
   makeWithRef: Hooks$WithRef$makeWithRef
 };
 
-var testForwardRef = React.forwardRef(function (param, param$1) {
-      return makeWithRef(param.vehicle)(param$1);
-    });
+let testForwardRef = React.forwardRef(function (param, param$1) {
+  return makeWithRef(param.vehicle)(param$1);
+});
 
-var input = React.forwardRef(function (Props, param) {
-      var partial_arg = Props.r;
-      return React.createElement("div", {
-                  ref: param
-                }, partial_arg.x);
-    });
+let input = React.forwardRef(function (Props, param) {
+  let partial_arg = Props.r;
+  return React.createElement("div", {
+    ref: param
+  }, partial_arg.x);
+});
 
-var ForwardRef = {
+let ForwardRef = {
   input: input
 };
 
 function Hooks$Poly$polymorphicComponent(Props) {
-  var param = Props.p;
+  let param = Props.p;
   return param[0].name;
 }
 
-var Poly = {
+let Poly = {
   polymorphicComponent: Hooks$Poly$polymorphicComponent
 };
 
@@ -162,62 +162,62 @@ function Hooks$Fun$functionReturningReactElement(Props) {
   return Props.name;
 }
 
-var Fun = {
+let Fun = {
   functionReturningReactElement: Hooks$Fun$functionReturningReactElement
 };
 
 function Hooks$RenderPropRequiresConversion(Props) {
-  var renderVehicle = Props.renderVehicle;
+  let renderVehicle = Props.renderVehicle;
   return Curry._1(renderVehicle, {
-              vehicle: {
-                name: "Car"
-              },
-              number: 42
-            });
+    vehicle: {
+      name: "Car"
+    },
+    number: 42
+  });
 }
 
-var RenderPropRequiresConversion = {
+let RenderPropRequiresConversion = {
   make: Hooks$RenderPropRequiresConversion
 };
 
 function Hooks$WithChildren$aComponentWithChildren(Props) {
-  var vehicle = Props.vehicle;
-  var children = Props.children;
+  let vehicle = Props.vehicle;
+  let children = Props.children;
   return React.createElement("div", undefined, "Another Hook " + vehicle.name, React.createElement("div", undefined, children));
 }
 
-var WithChildren = {
+let WithChildren = {
   aComponentWithChildren: Hooks$WithChildren$aComponentWithChildren
 };
 
 function Hooks$DD(Props) {
-  var name = Props.name;
+  let name = Props.name;
   return name;
 }
 
-var DD = {
+let DD = {
   make: Hooks$DD
 };
 
-var make = Hooks;
+let make = Hooks;
 
-var $$default = Hooks;
+let $$default = Hooks;
 
 export {
-  make ,
+  make,
   $$default as default,
-  Another ,
-  Inner ,
-  NoProps ,
-  functionWithRenamedArgs ,
-  WithRename ,
-  WithRef ,
-  testForwardRef ,
-  ForwardRef ,
-  Poly ,
-  Fun ,
-  RenderPropRequiresConversion ,
-  WithChildren ,
-  DD ,
+  Another,
+  Inner,
+  NoProps,
+  functionWithRenamedArgs,
+  WithRename,
+  WithRef,
+  testForwardRef,
+  ForwardRef,
+  Poly,
+  Fun,
+  RenderPropRequiresConversion,
+  WithChildren,
+  DD,
 }
 /* testForwardRef Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImmutableArray.res.js b/jscomp/gentype_tests/typescript-react-example/src/ImmutableArray.res.js
index e443f7f254..561b6f8896 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImmutableArray.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImmutableArray.res.js
@@ -18,9 +18,9 @@ function size(a) {
   return a.length;
 }
 
-var get = Belt_Array.get;
+let get = Belt_Array.get;
 
-var getExn = Belt_Array.getExn;
+let getExn = Belt_Array.getExn;
 
 function getUnsafe(a, x) {
   return a[x];
@@ -30,9 +30,9 @@ function getUndefined(a, x) {
   return a[x];
 }
 
-var shuffle = Belt_Array.shuffle;
+let shuffle = Belt_Array.shuffle;
 
-var reverse = Belt_Array.reverse;
+let reverse = Belt_Array.reverse;
 
 function makeUninitialized(x) {
   return new Array(x);
@@ -42,169 +42,169 @@ function makeUninitializedUnsafe(x) {
   return new Array(x);
 }
 
-var make = Belt_Array.make;
+let make = Belt_Array.make;
 
-var range = Belt_Array.range;
+let range = Belt_Array.range;
 
-var rangeBy = Belt_Array.rangeBy;
+let rangeBy = Belt_Array.rangeBy;
 
-var makeByU = Belt_Array.makeByU;
+let makeByU = Belt_Array.makeByU;
 
-var makeBy = Belt_Array.makeBy;
+let makeBy = Belt_Array.makeBy;
 
-var makeByAndShuffleU = Belt_Array.makeByAndShuffleU;
+let makeByAndShuffleU = Belt_Array.makeByAndShuffleU;
 
-var makeByAndShuffle = Belt_Array.makeByAndShuffle;
+let makeByAndShuffle = Belt_Array.makeByAndShuffle;
 
-var zip = Belt_Array.zip;
+let zip = Belt_Array.zip;
 
-var zipByU = Belt_Array.zipByU;
+let zipByU = Belt_Array.zipByU;
 
-var zipBy = Belt_Array.zipBy;
+let zipBy = Belt_Array.zipBy;
 
-var unzip = Belt_Array.unzip;
+let unzip = Belt_Array.unzip;
 
-var concat = Belt_Array.concat;
+let concat = Belt_Array.concat;
 
-var concatMany = Belt_Array.concatMany;
+let concatMany = Belt_Array.concatMany;
 
-var slice = Belt_Array.slice;
+let slice = Belt_Array.slice;
 
-var sliceToEnd = Belt_Array.sliceToEnd;
+let sliceToEnd = Belt_Array.sliceToEnd;
 
 function copy(a) {
   return a.slice(0);
 }
 
-var forEachU = Belt_Array.forEachU;
+let forEachU = Belt_Array.forEachU;
 
-var forEach = Belt_Array.forEach;
+let forEach = Belt_Array.forEach;
 
-var mapU = Belt_Array.mapU;
+let mapU = Belt_Array.mapU;
 
-var map = Belt_Array.map;
+let map = Belt_Array.map;
 
-var keepWithIndexU = Belt_Array.keepWithIndexU;
+let keepWithIndexU = Belt_Array.keepWithIndexU;
 
-var keepWithIndex = Belt_Array.keepWithIndex;
+let keepWithIndex = Belt_Array.keepWithIndex;
 
-var keepMapU = Belt_Array.keepMapU;
+let keepMapU = Belt_Array.keepMapU;
 
-var keepMap = Belt_Array.keepMap;
+let keepMap = Belt_Array.keepMap;
 
-var forEachWithIndexU = Belt_Array.forEachWithIndexU;
+let forEachWithIndexU = Belt_Array.forEachWithIndexU;
 
-var forEachWithIndex = Belt_Array.forEachWithIndex;
+let forEachWithIndex = Belt_Array.forEachWithIndex;
 
-var mapWithIndexU = Belt_Array.mapWithIndexU;
+let mapWithIndexU = Belt_Array.mapWithIndexU;
 
-var mapWithIndex = Belt_Array.mapWithIndex;
+let mapWithIndex = Belt_Array.mapWithIndex;
 
-var partitionU = Belt_Array.partitionU;
+let partitionU = Belt_Array.partitionU;
 
-var partition = Belt_Array.partition;
+let partition = Belt_Array.partition;
 
-var reduceU = Belt_Array.reduceU;
+let reduceU = Belt_Array.reduceU;
 
-var reduce = Belt_Array.reduce;
+let reduce = Belt_Array.reduce;
 
-var reduceReverseU = Belt_Array.reduceReverseU;
+let reduceReverseU = Belt_Array.reduceReverseU;
 
-var reduceReverse = Belt_Array.reduceReverse;
+let reduceReverse = Belt_Array.reduceReverse;
 
-var reduceReverse2U = Belt_Array.reduceReverse2U;
+let reduceReverse2U = Belt_Array.reduceReverse2U;
 
-var reduceReverse2 = Belt_Array.reduceReverse2;
+let reduceReverse2 = Belt_Array.reduceReverse2;
 
-var someU = Belt_Array.someU;
+let someU = Belt_Array.someU;
 
-var some = Belt_Array.some;
+let some = Belt_Array.some;
 
-var everyU = Belt_Array.everyU;
+let everyU = Belt_Array.everyU;
 
-var every = Belt_Array.every;
+let every = Belt_Array.every;
 
-var every2U = Belt_Array.every2U;
+let every2U = Belt_Array.every2U;
 
-var every2 = Belt_Array.every2;
+let every2 = Belt_Array.every2;
 
-var some2U = Belt_Array.some2U;
+let some2U = Belt_Array.some2U;
 
-var some2 = Belt_Array.some2;
+let some2 = Belt_Array.some2;
 
-var cmpU = Belt_Array.cmpU;
+let cmpU = Belt_Array.cmpU;
 
-var cmp = Belt_Array.cmp;
+let cmp = Belt_Array.cmp;
 
-var eqU = Belt_Array.eqU;
+let eqU = Belt_Array.eqU;
 
-var eq = Belt_Array.eq;
+let eq = Belt_Array.eq;
 
-var $$Array$1 = {
+let $$Array$1 = {
   get: get
 };
 
 export {
   $$Array$1 as $$Array,
-  fromArray ,
-  toArray ,
-  length ,
-  size ,
-  get ,
-  getExn ,
-  getUnsafe ,
-  getUndefined ,
-  shuffle ,
-  reverse ,
-  makeUninitialized ,
-  makeUninitializedUnsafe ,
-  make ,
-  range ,
-  rangeBy ,
-  makeByU ,
-  makeBy ,
-  makeByAndShuffleU ,
-  makeByAndShuffle ,
-  zip ,
-  zipByU ,
-  zipBy ,
-  unzip ,
-  concat ,
-  concatMany ,
-  slice ,
-  sliceToEnd ,
-  copy ,
-  forEachU ,
-  forEach ,
-  mapU ,
-  map ,
-  keepWithIndexU ,
-  keepWithIndex ,
-  keepMapU ,
-  keepMap ,
-  forEachWithIndexU ,
-  forEachWithIndex ,
-  mapWithIndexU ,
-  mapWithIndex ,
-  partitionU ,
-  partition ,
-  reduceU ,
-  reduce ,
-  reduceReverseU ,
-  reduceReverse ,
-  reduceReverse2U ,
-  reduceReverse2 ,
-  someU ,
-  some ,
-  everyU ,
-  every ,
-  every2U ,
-  every2 ,
-  some2U ,
-  some2 ,
-  cmpU ,
-  cmp ,
-  eqU ,
-  eq ,
+  fromArray,
+  toArray,
+  length,
+  size,
+  get,
+  getExn,
+  getUnsafe,
+  getUndefined,
+  shuffle,
+  reverse,
+  makeUninitialized,
+  makeUninitializedUnsafe,
+  make,
+  range,
+  rangeBy,
+  makeByU,
+  makeBy,
+  makeByAndShuffleU,
+  makeByAndShuffle,
+  zip,
+  zipByU,
+  zipBy,
+  unzip,
+  concat,
+  concatMany,
+  slice,
+  sliceToEnd,
+  copy,
+  forEachU,
+  forEach,
+  mapU,
+  map,
+  keepWithIndexU,
+  keepWithIndex,
+  keepMapU,
+  keepMap,
+  forEachWithIndexU,
+  forEachWithIndex,
+  mapWithIndexU,
+  mapWithIndex,
+  partitionU,
+  partition,
+  reduceU,
+  reduce,
+  reduceReverseU,
+  reduceReverse,
+  reduceReverse2U,
+  reduceReverse2,
+  someU,
+  some,
+  everyU,
+  every,
+  every2U,
+  every2,
+  some2U,
+  some2,
+  cmpU,
+  cmp,
+  eqU,
+  eq,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.res.js b/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.res.js
index 6356fbdd4c..8b5cb1e464 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportHookDefault.res.js
@@ -3,16 +3,16 @@
 import ImportHookDefaultGen from "./ImportHookDefault.gen";
 import * as ImportHookDefaultGen$1 from "./ImportHookDefault.gen";
 
-var make = ImportHookDefaultGen$1.make;
+let make = ImportHookDefaultGen$1.make;
 
-var make2 = ImportHookDefaultGen;
+let make2 = ImportHookDefaultGen;
 
-var MM = {
+let MM = {
   make2: make2
 };
 
 export {
-  make ,
-  MM ,
+  make,
+  MM,
 }
 /* make Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.res.js b/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.res.js
index 0a3f6aa513..8bcba0f408 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportHooks.res.js
@@ -2,14 +2,14 @@
 
 import * as ImportHooksGen from "./ImportHooks.gen";
 
-var make = ImportHooksGen.makeRenamed;
+let make = ImportHooksGen.makeRenamed;
 
 function foo(prim) {
   return ImportHooksGen.foo(prim);
 }
 
 export {
-  make ,
-  foo ,
+  make,
+  foo,
 }
 /* make Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.res.js b/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.res.js
index f8da735e19..34ab9cf267 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportIndex.res.js
@@ -2,9 +2,9 @@
 
 import ImportIndexGen from "./ImportIndex.gen";
 
-var make = ImportIndexGen;
+let make = ImportIndexGen;
 
 export {
-  make ,
+  make,
 }
 /* make Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.res.js b/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.res.js
index 69f8ca32c7..84f321dd72 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ImportJsValue.res.js
@@ -19,19 +19,19 @@ function returnMixedArray(prim) {
   return ImportJsValueGen$1.returnMixedArray();
 }
 
-var roundedNumber = ImportJsValueGen$1.round(1.8);
+let roundedNumber = ImportJsValueGen$1.round(1.8);
 
-var areaValue = ImportJsValueGen$1.area({
-      x: 3,
-      y: undefined
-    });
+let areaValue = ImportJsValueGen$1.area({
+  x: 3,
+  y: undefined
+});
 
 function getAbs(x) {
-  var getAbs$1 = x.getAbs;
+  let getAbs$1 = x.getAbs;
   return getAbs$1();
 }
 
-var AbsoluteValue = {
+let AbsoluteValue = {
   getAbs: getAbs
 };
 
@@ -51,9 +51,9 @@ function higherOrder(prim) {
   return ImportJsValueGen$1.higherOrder(prim);
 }
 
-var returnedFromHigherOrder = ImportJsValueGen$1.higherOrder(function (prim0, prim1) {
-      return prim0 + prim1 | 0;
-    });
+let returnedFromHigherOrder = ImportJsValueGen$1.higherOrder(function (prim0, prim1) {
+  return prim0 + prim1 | 0;
+});
 
 function convertVariant(prim) {
   return ImportJsValueGen$1.convertVariant(prim);
@@ -63,23 +63,23 @@ function polymorphic(prim) {
   return ImportJsValueGen$1.polymorphic(prim);
 }
 
-var $$default = ImportJsValueGen;
+let $$default = ImportJsValueGen;
 
 export {
-  round ,
-  round2 ,
-  area ,
-  returnMixedArray ,
-  roundedNumber ,
-  areaValue ,
-  AbsoluteValue ,
-  useGetProp ,
-  useGetAbs ,
-  useColor ,
-  higherOrder ,
-  returnedFromHigherOrder ,
-  convertVariant ,
-  polymorphic ,
+  round,
+  round2,
+  area,
+  returnMixedArray,
+  roundedNumber,
+  areaValue,
+  AbsoluteValue,
+  useGetProp,
+  useGetAbs,
+  useColor,
+  higherOrder,
+  returnedFromHigherOrder,
+  convertVariant,
+  polymorphic,
   $$default as default,
 }
 /* roundedNumber Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/InnerModuleSignature.res.js b/jscomp/gentype_tests/typescript-react-example/src/InnerModuleSignature.res.js
index db7df4631b..047a40e2a9 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/InnerModuleSignature.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/InnerModuleSignature.res.js
@@ -5,11 +5,11 @@ function make(t) {
   return t + "...";
 }
 
-var InnerModule = {
+let InnerModule = {
   make: make
 };
 
 export {
-  InnerModule ,
+  InnerModule,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/JSXV4.res.js b/jscomp/gentype_tests/typescript-react-example/src/JSXV4.res.js
index 7fec15984d..bd037b53c3 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/JSXV4.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/JSXV4.res.js
@@ -6,7 +6,7 @@ function JSXV4$CompV4(props) {
   return props.x + props.y;
 }
 
-var CompV4 = {
+let CompV4 = {
   make: JSXV4$CompV4
 };
 
@@ -14,15 +14,15 @@ function JSXV4$CompV3(Props) {
   return Props.x + Props.y;
 }
 
-var CompV3 = {
+let CompV3 = {
   make: JSXV4$CompV3
 };
 
-var make = JSXV4Gen.make;
+let make = JSXV4Gen.make;
 
 export {
-  CompV4 ,
-  CompV3 ,
-  make ,
+  CompV4,
+  CompV3,
+  make,
 }
 /* make Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/LabeledFun.res.js b/jscomp/gentype_tests/typescript-react-example/src/LabeledFun.res.js
index 2be82a13b9..347d70ab58 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/LabeledFun.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/LabeledFun.res.js
@@ -2,11 +2,11 @@
 
 
 function labelled(a, bOpt, c, d, e, f) {
-  var b = bOpt !== undefined ? bOpt : 3;
+  let b = bOpt !== undefined ? bOpt : 3;
   return ((((a + b | 0) + c | 0) + d | 0) + e | 0) + f | 0;
 }
 
 export {
-  labelled ,
+  labelled,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/LetPrivate.res.js b/jscomp/gentype_tests/typescript-react-example/src/LetPrivate.res.js
index d8727696b1..a84e43e81b 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/LetPrivate.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/LetPrivate.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var y = 34;
+let y = 34;
 
 export {
-  y ,
+  y,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Lib.res.js b/jscomp/gentype_tests/typescript-react-example/src/Lib.res.js
index 744468f41f..42b9876281 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Lib.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Lib.res.js
@@ -1,18 +1,18 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var a = {
+let a = {
   action: "A",
   _0: "a"
 };
 
-var b = {
+let b = {
   action: "B",
   _0: "b"
 };
 
 export {
-  a ,
-  b ,
+  a,
+  b,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Machine.res.js b/jscomp/gentype_tests/typescript-react-example/src/Machine.res.js
index 6ec89819c8..ac82a31dc6 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Machine.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Machine.res.js
@@ -1,12 +1,12 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var a = {
+let a = {
   TAG: "A",
   _0: 3
 };
 
 export {
-  a ,
+  a,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases.res.js b/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases.res.js
index 0ff799c80a..8ef8bd5d7e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases.res.js
@@ -1,20 +1,20 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var Inner = {};
+let Inner = {};
 
-var Outer = {
+let Outer = {
   Inner: Inner
 };
 
-var InnerNested = {};
+let InnerNested = {};
 
-var Inner2 = {
+let Inner2 = {
   InnerNested: InnerNested,
   OuterInnerAlias2: undefined
 };
 
-var Outer2 = {
+let Outer2 = {
   OuterInnerAlias: undefined,
   Inner2: Inner2
 };
@@ -31,17 +31,17 @@ function testInner2(x) {
   return x;
 }
 
-var Outer2Alias;
+let Outer2Alias;
 
-var InnerNestedAlias;
+let InnerNestedAlias;
 
 export {
-  Outer ,
-  Outer2 ,
-  Outer2Alias ,
-  InnerNestedAlias ,
-  testNested ,
-  testInner ,
-  testInner2 ,
+  Outer,
+  Outer2,
+  Outer2Alias,
+  InnerNestedAlias,
+  testNested,
+  testInner,
+  testInner2,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases2.res.js b/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases2.res.js
index 4be3b8371a..4bab09f7da 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases2.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/ModuleAliases2.res.js
@@ -1,22 +1,22 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var Inner = {};
+let Inner = {};
 
-var Outer = {
+let Outer = {
   Inner: Inner
 };
 
-var OuterAlias;
+let OuterAlias;
 
-var InnerAlias;
+let InnerAlias;
 
-var q = 42;
+let q = 42;
 
 export {
-  Outer ,
-  OuterAlias ,
-  InnerAlias ,
-  q ,
+  Outer,
+  OuterAlias,
+  InnerAlias,
+  q,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/MoreVariants.res.js b/jscomp/gentype_tests/typescript-react-example/src/MoreVariants.res.js
index 833cc29532..c03d6905b3 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/MoreVariants.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/MoreVariants.res.js
@@ -10,7 +10,7 @@ function testWithoutRenaming(x) {
 }
 
 export {
-  testWithRenaming ,
-  testWithoutRenaming ,
+  testWithRenaming,
+  testWithoutRenaming,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/MyInput.res.js b/jscomp/gentype_tests/typescript-react-example/src/MyInput.res.js
index 3aa6ca7d77..6fdab560cb 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/MyInput.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/MyInput.res.js
@@ -2,9 +2,9 @@
 
 import MyInputGen from "./MyInput.gen";
 
-var make = MyInputGen;
+let make = MyInputGen;
 
 export {
-  make ,
+  make,
 }
 /* make Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/MyModule.res.js b/jscomp/gentype_tests/typescript-react-example/src/MyModule.res.js
index 3377033068..6970a7afc7 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/MyModule.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/MyModule.res.js
@@ -6,6 +6,6 @@ function add(a, b) {
 }
 
 export {
-  add ,
+  add,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/NestedModules.res.js b/jscomp/gentype_tests/typescript-react-example/src/NestedModules.res.js
index 654fd2e5ad..24d7716673 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/NestedModules.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/NestedModules.res.js
@@ -5,7 +5,7 @@ function nested3Function(x) {
   return x;
 }
 
-var Nested3 = {
+let Nested3 = {
   x: 0,
   y: 1,
   z: 2,
@@ -18,7 +18,7 @@ function nested2Function(x) {
   return x;
 }
 
-var Nested2 = {
+let Nested2 = {
   x: 0,
   nested2Value: 1,
   y: 2,
@@ -26,17 +26,17 @@ var Nested2 = {
   nested2Function: nested2Function
 };
 
-var Universe = {
+let Universe = {
   theAnswer: 42,
   notExported: 33,
   Nested2: Nested2,
   someString: "some exported string"
 };
 
-var notNested = 1;
+let notNested = 1;
 
 export {
-  notNested ,
-  Universe ,
+  notNested,
+  Universe,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/NestedModulesInSignature.res.js b/jscomp/gentype_tests/typescript-react-example/src/NestedModulesInSignature.res.js
index 394291d726..336fced047 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/NestedModulesInSignature.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/NestedModulesInSignature.res.js
@@ -1,11 +1,11 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var Universe = {
+let Universe = {
   theAnswer: 42
 };
 
 export {
-  Universe ,
+  Universe,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/NestedVariants.res.js b/jscomp/gentype_tests/typescript-react-example/src/NestedVariants.res.js
index 81711cbe59..008273bbc4 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/NestedVariants.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/NestedVariants.res.js
@@ -3,113 +3,113 @@
 
 function makeVariant(param) {
   return {
-          TAG: "NonUnary",
-          _0: 5,
-          _1: 3
-        };
+    TAG: "NonUnary",
+    _0: 5,
+    _1: 3
+  };
 }
 
 function makeABC(param) {
   return {
-          TAG: "A",
-          _0: {
-            c: {
-              TAG: "C",
-              _0: "a string"
-            }
-          },
-          _1: 5
-        };
+    TAG: "A",
+    _0: {
+      c: {
+        TAG: "C",
+        _0: "a string"
+      }
+    },
+    _1: 5
+  };
 }
 
 function makeBC(param) {
   return {
-          c: {
-            TAG: "C",
-            _0: "a string"
-          }
-        };
+    c: {
+      TAG: "C",
+      _0: "a string"
+    }
+  };
 }
 
 function makeAC(param) {
   return {
-          TAG: "A",
-          _0: {
-            TAG: "C",
-            _0: "a string"
-          },
-          _1: 5
-        };
+    TAG: "A",
+    _0: {
+      TAG: "C",
+      _0: "a string"
+    },
+    _1: 5
+  };
 }
 
 function makeAD(param) {
   return {
-          TAG: "A",
-          _0: {
-            TAG: "Int",
-            _0: 3
-          },
-          _1: 5
-        };
+    TAG: "A",
+    _0: {
+      TAG: "Int",
+      _0: 3
+    },
+    _1: 5
+  };
 }
 
 function makeAE(param) {
   return {
-          TAG: "A",
-          _0: 3,
-          _1: 5
-        };
+    TAG: "A",
+    _0: 3,
+    _1: 5
+  };
 }
 
 function makeFD(param) {
   return {
-          TAG: "F",
-          _0: {
-            TAG: "Int",
-            _0: 3
-          }
-        };
+    TAG: "F",
+    _0: {
+      TAG: "Int",
+      _0: 3
+    }
+  };
 }
 
 function makeHD(param) {
   return {
-          TAG: "H",
-          _0: {
-            TAG: "Int",
-            _0: 5
-          },
-          _1: 5
-        };
+    TAG: "H",
+    _0: {
+      TAG: "Int",
+      _0: 5
+    },
+    _1: 5
+  };
 }
 
 function makeJ(param) {
   return {
-          TAG: "J",
-          _0: {
-            TAG: "Int",
-            _0: 5
-          },
-          _1: {
-            TAG: "Int",
-            _0: 3
-          }
-        };
+    TAG: "J",
+    _0: {
+      TAG: "Int",
+      _0: 5
+    },
+    _1: {
+      TAG: "Int",
+      _0: 3
+    }
+  };
 }
 
 function makeK(param) {
   return {
-          TAG: "K",
-          _0: [
-            {
-              TAG: "Int",
-              _0: 5
-            },
-            {
-              TAG: "Int",
-              _0: 3
-            }
-          ]
-        };
+    TAG: "K",
+    _0: [
+      {
+        TAG: "Int",
+        _0: 5
+      },
+      {
+        TAG: "Int",
+        _0: 3
+      }
+    ]
+  };
 }
 
 function testBoxedBinary(param) {
@@ -124,40 +124,40 @@ function testInline(x) {
   switch (x.TAG) {
     case "I" :
         return {
-                TAG: "I",
-                i: x.i,
-                j: x.j
-              };
+          TAG: "I",
+          i: x.i,
+          j: x.j
+        };
     case "J" :
         return x;
     case "K" :
         return {
-                TAG: "K",
-                _0: x._1,
-                _1: x._0
-              };
+          TAG: "K",
+          _0: x._1,
+          _1: x._0
+        };
     case "L" :
         return {
-                TAG: "L",
-                _0: x._0
-              };
+          TAG: "L",
+          _0: x._0
+        };
     
   }
 }
 
 export {
-  makeVariant ,
-  makeABC ,
-  makeBC ,
-  makeAC ,
-  makeAD ,
-  makeAE ,
-  makeFD ,
-  makeHD ,
-  makeJ ,
-  makeK ,
-  testBoxedBinary ,
-  testUnboxedBinary ,
-  testInline ,
+  makeVariant,
+  makeABC,
+  makeBC,
+  makeAC,
+  makeAD,
+  makeAE,
+  makeFD,
+  makeHD,
+  makeJ,
+  makeK,
+  testBoxedBinary,
+  testUnboxedBinary,
+  testInline,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/NonrecursiveTypes.res.js b/jscomp/gentype_tests/typescript-react-example/src/NonrecursiveTypes.res.js
index 44a5721747..c0395eb74e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/NonrecursiveTypes.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/NonrecursiveTypes.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var M = {};
+let M = {};
 
 export {
-  M ,
+  M,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Object.res.js b/jscomp/gentype_tests/typescript-react-example/src/Object.res.js
index e4b301d888..9af5f5408e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Object.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Object.res.js
@@ -1,18 +1,18 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var st = {
+let st = {
   crop: undefined,
   "fp-z": undefined
 };
 
-var st2 = {
+let st2 = {
   crop: undefined,
   "fp-z": undefined
 };
 
 export {
-  st ,
-  st2 ,
+  st,
+  st2,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/OnClick2.res.js b/jscomp/gentype_tests/typescript-react-example/src/OnClick2.res.js
index 61e88f26b1..ebe3a61f47 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/OnClick2.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/OnClick2.res.js
@@ -3,15 +3,15 @@
 import * as React from "react";
 
 function OnClick2(Props) {
-  var onClick = Props.onClick;
+  let onClick = Props.onClick;
   return React.createElement("div", {
-              onClick: onClick
-            });
+    onClick: onClick
+  });
 }
 
-var make = OnClick2;
+let make = OnClick2;
 
 export {
-  make ,
+  make,
 }
 /* react Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Opaque.res.js b/jscomp/gentype_tests/typescript-react-example/src/Opaque.res.js
index 7639ea3f14..ce8507806e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Opaque.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Opaque.res.js
@@ -10,7 +10,7 @@ function testConvertNestedRecordFromOtherFile(x) {
 }
 
 export {
-  noConversion ,
-  testConvertNestedRecordFromOtherFile ,
+  noConversion,
+  testConvertNestedRecordFromOtherFile,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Records.res.js b/jscomp/gentype_tests/typescript-react-example/src/Records.res.js
index f72740474c..36bff49322 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Records.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Records.res.js
@@ -7,45 +7,45 @@ import * as Caml_option from "rescript/lib/es6/caml_option.js";
 
 function computeArea(param) {
   return Math.imul(Math.imul(param.x, param.y), Belt_Option.mapWithDefault(param.z, 1, (function (n) {
-                    return n;
-                  })));
+    return n;
+  })));
 }
 
 function coord2d(x, y) {
   return {
-          x: x,
-          y: y,
-          z: undefined
-        };
+    x: x,
+    y: y,
+    z: undefined
+  };
 }
 
-var getOpt = Belt_Option.mapWithDefault;
+let getOpt = Belt_Option.mapWithDefault;
 
 function findAddress(business) {
   return Belt_Option.mapWithDefault(business.address, /* [] */0, (function (a) {
-                return {
-                        hd: a,
-                        tl: /* [] */0
-                      };
-              }));
+    return {
+      hd: a,
+      tl: /* [] */0
+    };
+  }));
 }
 
 function findAllAddresses(businesses) {
   return Belt_List.toArray(Belt_List.flatten(Belt_List.fromArray(Belt_Array.map(businesses, (function (business) {
-                            return Belt_List.concat(Belt_Option.mapWithDefault(business.address, /* [] */0, (function (a) {
-                                              return {
-                                                      hd: a,
-                                                      tl: /* [] */0
-                                                    };
-                                            })), Belt_Option.mapWithDefault(business.owner, /* [] */0, (function (p) {
-                                              return Belt_Option.mapWithDefault(p.address, /* [] */0, (function (a) {
-                                                            return {
-                                                                    hd: a,
-                                                                    tl: /* [] */0
-                                                                  };
-                                                          }));
-                                            })));
-                          })))));
+    return Belt_List.concat(Belt_Option.mapWithDefault(business.address, /* [] */0, (function (a) {
+      return {
+        hd: a,
+        tl: /* [] */0
+      };
+    })), Belt_Option.mapWithDefault(business.owner, /* [] */0, (function (p) {
+      return Belt_Option.mapWithDefault(p.address, /* [] */0, (function (a) {
+        return {
+          hd: a,
+          tl: /* [] */0
+        };
+      }));
+    })));
+  })))));
 }
 
 function getPayload(param) {
@@ -56,38 +56,38 @@ function getPayloadRecord(param) {
   return param.payload;
 }
 
-var recordValue = {
+let recordValue = {
   v: 1,
   w: 1
 };
 
-var payloadValue = {
+let payloadValue = {
   num: 1,
   payload: recordValue
 };
 
 function getPayloadRecordPlusOne(param) {
-  var payload = param.payload;
+  let payload = param.payload;
   return {
-          v: payload.v + 1 | 0,
-          w: payload.w
-        };
+    v: payload.v + 1 | 0,
+    w: payload.w
+  };
 }
 
 function findAddress2(business) {
   return Belt_Option.mapWithDefault(Caml_option.nullable_to_opt(business.address2), /* [] */0, (function (a) {
-                return {
-                        hd: a,
-                        tl: /* [] */0
-                      };
-              }));
+    return {
+      hd: a,
+      tl: /* [] */0
+    };
+  }));
 }
 
-var someBusiness2_owner = null;
+let someBusiness2_owner = null;
 
-var someBusiness2_address2 = null;
+let someBusiness2_address2 = null;
 
-var someBusiness2 = {
+let someBusiness2 = {
   name: "SomeBusiness",
   owner: someBusiness2_owner,
   address2: someBusiness2_address2
@@ -95,14 +95,14 @@ var someBusiness2 = {
 
 function computeArea3(o) {
   return Math.imul(Math.imul(o.x, o.y), Belt_Option.mapWithDefault(Caml_option.nullable_to_opt(o.z), 1, (function (n) {
-                    return n;
-                  })));
+    return n;
+  })));
 }
 
 function computeArea4(o) {
   return Math.imul(Math.imul(o.x, o.y), Belt_Option.mapWithDefault(o.z, 1, (function (n) {
-                    return n;
-                  })));
+    return n;
+  })));
 }
 
 function testMyRec(x) {
@@ -123,53 +123,53 @@ function testMyObj2(x) {
 
 function testMyRecBsAs(x) {
   return [
-          x.jsValid0,
-          x.type,
-          x["the-key"],
-          x["with\\\"dquote"],
-          x["with'squote"],
-          x["1number"]
-        ];
+    x.jsValid0,
+    x.type,
+    x["the-key"],
+    x["with\\\"dquote"],
+    x["with'squote"],
+    x["1number"]
+  ];
 }
 
 function testMyRecBsAs2(x) {
   return x;
 }
 
-var origin = {
+let origin = {
   x: 0,
   y: 0,
   z: 0
 };
 
-var someBusiness = {
+let someBusiness = {
   name: "SomeBusiness",
   owner: undefined,
   address: undefined
 };
 
 export {
-  origin ,
-  computeArea ,
-  coord2d ,
-  getOpt ,
-  findAddress ,
-  someBusiness ,
-  findAllAddresses ,
-  getPayload ,
-  getPayloadRecord ,
-  recordValue ,
-  payloadValue ,
-  getPayloadRecordPlusOne ,
-  findAddress2 ,
-  someBusiness2 ,
-  computeArea3 ,
-  computeArea4 ,
-  testMyRec ,
-  testMyRec2 ,
-  testMyObj ,
-  testMyObj2 ,
-  testMyRecBsAs ,
-  testMyRecBsAs2 ,
+  origin,
+  computeArea,
+  coord2d,
+  getOpt,
+  findAddress,
+  someBusiness,
+  findAllAddresses,
+  getPayload,
+  getPayloadRecord,
+  recordValue,
+  payloadValue,
+  getPayloadRecordPlusOne,
+  findAddress2,
+  someBusiness2,
+  computeArea3,
+  computeArea4,
+  testMyRec,
+  testMyRec2,
+  testMyObj,
+  testMyObj2,
+  testMyRecBsAs,
+  testMyRecBsAs2,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/References.res.js b/jscomp/gentype_tests/typescript-react-example/src/References.res.js
index b0b4088d58..ab19e92b23 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/References.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/References.res.js
@@ -3,8 +3,8 @@
 
 function create(x) {
   return {
-          contents: x
-        };
+    contents: x
+  };
 }
 
 function access(r) {
@@ -21,15 +21,15 @@ function get(r) {
 
 function make(prim) {
   return {
-          contents: prim
-        };
+    contents: prim
+  };
 }
 
 function set(r, v) {
   r.contents = v;
 }
 
-var R = {
+let R = {
   get: get,
   make: make,
   set: set
@@ -44,14 +44,14 @@ function preserveRefIdentity(x) {
 }
 
 export {
-  create ,
-  access ,
-  update ,
-  R ,
-  get ,
-  make ,
-  set ,
-  destroysRefIdentity ,
-  preserveRefIdentity ,
+  create,
+  access,
+  update,
+  R,
+  get,
+  make,
+  set,
+  destroysRefIdentity,
+  preserveRefIdentity,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Shadow.res.js b/jscomp/gentype_tests/typescript-react-example/src/Shadow.res.js
index 87be066e3f..17539ddd9e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Shadow.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Shadow.res.js
@@ -9,12 +9,12 @@ function test$1(param) {
   return "a";
 }
 
-var M = {
+let M = {
   test: test$1
 };
 
 export {
-  test ,
-  M ,
+  test,
+  M,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TestEmitInnerModules.res.js b/jscomp/gentype_tests/typescript-react-example/src/TestEmitInnerModules.res.js
index 995314b4f9..af291932db 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TestEmitInnerModules.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TestEmitInnerModules.res.js
@@ -1,25 +1,25 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var Inner = {
+let Inner = {
   x: 34,
   y: "hello"
 };
 
-var Inner$1 = {
+let Inner$1 = {
   y: 44
 };
 
-var Medium = {
+let Medium = {
   Inner: Inner$1
 };
 
-var Outer = {
+let Outer = {
   Medium: Medium
 };
 
 export {
-  Inner ,
-  Outer ,
+  Inner,
+  Outer,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TestFirstClassModules.res.js b/jscomp/gentype_tests/typescript-react-example/src/TestFirstClassModules.res.js
index bef4b0e21b..3ff25e22b3 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TestFirstClassModules.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TestFirstClassModules.res.js
@@ -18,9 +18,9 @@ function convertFirstClassModuleWithTypeEquations(x) {
 }
 
 export {
-  convert ,
-  convertInterface ,
-  convertRecord ,
-  convertFirstClassModuleWithTypeEquations ,
+  convert,
+  convertInterface,
+  convertRecord,
+  convertFirstClassModuleWithTypeEquations,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TestImmutableArray.res.js b/jscomp/gentype_tests/typescript-react-example/src/TestImmutableArray.res.js
index 4cba8d864a..312ac2d9a9 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TestImmutableArray.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TestImmutableArray.res.js
@@ -16,8 +16,8 @@ function testBeltArraySet(arr) {
 }
 
 export {
-  testImmutableArrayGet ,
-  testBeltArrayGet ,
-  testBeltArraySet ,
+  testImmutableArrayGet,
+  testBeltArrayGet,
+  testBeltArraySet,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TestModuleAliases.res.js b/jscomp/gentype_tests/typescript-react-example/src/TestModuleAliases.res.js
index cde0007a68..3dca4790bf 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TestModuleAliases.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TestModuleAliases.res.js
@@ -17,28 +17,28 @@ function testInner2Expanded(x) {
   return x;
 }
 
-var OtherFile;
+let OtherFile;
 
-var OtherFileAlias;
+let OtherFileAlias;
 
-var OuterAlias;
+let OuterAlias;
 
-var OtherFile1;
+let OtherFile1;
 
-var Outer2;
+let Outer2;
 
-var Inner2;
+let Inner2;
 
 export {
-  OtherFile ,
-  OtherFileAlias ,
-  OuterAlias ,
-  OtherFile1 ,
-  Outer2 ,
-  Inner2 ,
-  testInner1 ,
-  testInner1Expanded ,
-  testInner2 ,
-  testInner2Expanded ,
+  OtherFile,
+  OtherFileAlias,
+  OuterAlias,
+  OtherFile1,
+  Outer2,
+  Inner2,
+  testInner1,
+  testInner1Expanded,
+  testInner2,
+  testInner2Expanded,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TestPromise.res.js b/jscomp/gentype_tests/typescript-react-example/src/TestPromise.res.js
index 69f21a758c..c9bc0047e8 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TestPromise.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TestPromise.res.js
@@ -6,19 +6,19 @@ import * as Caml_option from "rescript/lib/es6/caml_option.js";
 
 function convert(param) {
   return Js_promise.then_((function (param) {
-                return Promise.resolve({
-                            result: param.s
-                          });
-              }), param);
+    return Promise.resolve({
+      result: param.s
+    });
+  }), param);
 }
 
 function barx(xOpt, param) {
-  var x = xOpt !== undefined ? Caml_option.valFromOption(xOpt) : Promise.resolve("a");
+  let x = xOpt !== undefined ? Caml_option.valFromOption(xOpt) : Promise.resolve("a");
   return Caml_obj.equal(x, x);
 }
 
 export {
-  convert ,
-  barx ,
+  convert,
+  barx,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType1.res.js b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType1.res.js
index 5fda66bee8..6af93bb13d 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType1.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType1.res.js
@@ -10,7 +10,7 @@ function convertAlias(x) {
 }
 
 export {
-  convert ,
-  convertAlias ,
+  convert,
+  convertAlias,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType2.res.js b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType2.res.js
index cf62be6e01..e28eba9775 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType2.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType2.res.js
@@ -6,6 +6,6 @@ function convertT2(x) {
 }
 
 export {
-  convertT2 ,
+  convertT2,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType3.res.js b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType3.res.js
index 77e8c2ac24..50b83d781b 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TransitiveType3.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TransitiveType3.res.js
@@ -6,6 +6,6 @@ function convertT3(x) {
 }
 
 export {
-  convertT3 ,
+  convertT3,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TypeNameSanitize.res.js b/jscomp/gentype_tests/typescript-react-example/src/TypeNameSanitize.res.js
index 44a5721747..c0395eb74e 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TypeNameSanitize.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TypeNameSanitize.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var M = {};
+let M = {};
 
 export {
-  M ,
+  M,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TypeParams1.res.js b/jscomp/gentype_tests/typescript-react-example/src/TypeParams1.res.js
index 99313ed03f..3cfa2aa5ea 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TypeParams1.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TypeParams1.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var exportSomething = 10;
+let exportSomething = 10;
 
 export {
-  exportSomething ,
+  exportSomething,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TypeParams2.res.js b/jscomp/gentype_tests/typescript-react-example/src/TypeParams2.res.js
index 99313ed03f..3cfa2aa5ea 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TypeParams2.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TypeParams2.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var exportSomething = 10;
+let exportSomething = 10;
 
 export {
-  exportSomething ,
+  exportSomething,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/TypeParams3.res.js b/jscomp/gentype_tests/typescript-react-example/src/TypeParams3.res.js
index 26ba896205..56541125c7 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/TypeParams3.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/TypeParams3.res.js
@@ -10,7 +10,7 @@ function test2(x) {
 }
 
 export {
-  test ,
-  test2 ,
+  test,
+  test2,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Unboxed.res.js b/jscomp/gentype_tests/typescript-react-example/src/Unboxed.res.js
index 7c02bf0833..ef4ba819f0 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Unboxed.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Unboxed.res.js
@@ -9,17 +9,17 @@ function r2Test(x) {
   return x;
 }
 
-var a = "0";
+let a = "0";
 
-var b = "1";
+let b = "1";
 
-var zero = 0;
+let zero = 0;
 
 export {
-  testV1 ,
-  r2Test ,
-  a ,
-  b ,
-  zero ,
+  testV1,
+  r2Test,
+  a,
+  b,
+  zero,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Uncurried.res.js b/jscomp/gentype_tests/typescript-react-example/src/Uncurried.res.js
index 5878196f58..55c163c146 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Uncurried.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Uncurried.res.js
@@ -59,17 +59,17 @@ function sumLblCurried(s, n) {
 }
 
 export {
-  uncurried0 ,
-  uncurried1 ,
-  uncurried2 ,
-  uncurried3 ,
-  curried3 ,
-  callback ,
-  callback2 ,
-  callback2U ,
-  sumU ,
-  sumU2 ,
-  sumCurried ,
-  sumLblCurried ,
+  uncurried0,
+  uncurried1,
+  uncurried2,
+  uncurried3,
+  curried3,
+  callback,
+  callback2,
+  callback2U,
+  sumU,
+  sumU2,
+  sumCurried,
+  sumLblCurried,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Usage.res.js b/jscomp/gentype_tests/typescript-react-example/src/Usage.res.js
index 602ee55bcb..f78594bf0c 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Usage.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Usage.res.js
@@ -2,12 +2,12 @@
 
 import * as MyModule from "./MyModule.res.js";
 
-var b = MyModule.add(5, 3);
+let b = MyModule.add(5, 3);
 
-var a = 5;
+let a = 5;
 
 export {
-  a ,
-  b ,
+  a,
+  b,
 }
 /* b Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/UseImportJsValue.res.js b/jscomp/gentype_tests/typescript-react-example/src/UseImportJsValue.res.js
index c954b150e0..f148eb32c0 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/UseImportJsValue.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/UseImportJsValue.res.js
@@ -10,7 +10,7 @@ function useTypeImportedInOtherModule(x) {
 }
 
 export {
-  useGetProp ,
-  useTypeImportedInOtherModule ,
+  useGetProp,
+  useTypeImportedInOtherModule,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Variants.res.js b/jscomp/gentype_tests/typescript-react-example/src/Variants.res.js
index 9f7f047d42..b20d106861 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Variants.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Variants.res.js
@@ -47,17 +47,17 @@ function id2(x) {
 
 function polyWithOpt(foo) {
   if (foo === "bar") {
-    return ;
+    return;
   } else if (foo !== "baz") {
     return {
-            NAME: "One",
-            VAL: foo
-          };
+      NAME: "One",
+      VAL: foo
+    };
   } else {
     return {
-            NAME: "Two",
-            VAL: 1
-          };
+      NAME: "Two",
+      VAL: 1
+    };
   }
 }
 
@@ -73,34 +73,34 @@ function restResult3(x) {
   return x;
 }
 
-var monday = "monday";
+let monday = "monday";
 
-var saturday = "saturday";
+let saturday = "saturday";
 
-var sunday = "sunday";
+let sunday = "sunday";
 
-var fortytwoOK = "fortytwo";
+let fortytwoOK = "fortytwo";
 
-var fortytwoBAD = "fortytwo";
+let fortytwoBAD = "fortytwo";
 
 export {
-  isWeekend ,
-  monday ,
-  saturday ,
-  sunday ,
-  onlySunday ,
-  swap ,
-  testConvert ,
-  fortytwoOK ,
-  fortytwoBAD ,
-  testConvert2 ,
-  testConvert3 ,
-  testConvert2to3 ,
-  id1 ,
-  id2 ,
-  polyWithOpt ,
-  restResult1 ,
-  restResult2 ,
-  restResult3 ,
+  isWeekend,
+  monday,
+  saturday,
+  sunday,
+  onlySunday,
+  swap,
+  testConvert,
+  fortytwoOK,
+  fortytwoBAD,
+  testConvert2,
+  testConvert3,
+  testConvert2to3,
+  id1,
+  id2,
+  polyWithOpt,
+  restResult1,
+  restResult2,
+  restResult3,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/VariantsWithPayload.res.js b/jscomp/gentype_tests/typescript-react-example/src/VariantsWithPayload.res.js
index b1bd1018b8..960efc433a 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/VariantsWithPayload.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/VariantsWithPayload.res.js
@@ -18,9 +18,9 @@ function printVariantWithPayload(x) {
     } else {
       console.log("printVariantWithPayload: Twenty");
     }
-    return ;
+    return;
   }
-  var payload = x.VAL;
+  let payload = x.VAL;
   console.log("printVariantWithPayload x:", payload.x, "y:", payload.y);
 }
 
@@ -29,16 +29,16 @@ function testManyPayloads(x) {
 }
 
 function printManyPayloads(x) {
-  var variant = x.NAME;
+  let variant = x.NAME;
   if (variant === "two") {
-    var match = x.VAL;
+    let match = x.VAL;
     console.log("printManyPayloads two:", match[0], match[1]);
-    return ;
+    return;
   }
   if (variant === "three") {
-    var payload = x.VAL;
+    let payload = x.VAL;
     console.log("printManyPayloads x:", payload.x, "y:", payload.y);
-    return ;
+    return;
   }
   console.log("printManyPayloads one:", x.VAL);
 }
@@ -54,22 +54,22 @@ function testVariantWithPayloads(x) {
 function printVariantWithPayloads(x) {
   if (typeof x !== "object") {
     console.log("printVariantWithPayloads", "A");
-    return ;
+    return;
   }
   switch (x.TAG) {
     case "B" :
         console.log("printVariantWithPayloads", "B(" + (String(x._0) + ")"));
-        return ;
+        return;
     case "C" :
         console.log("printVariantWithPayloads", "C(" + (String(x._0) + (", " + (String(x._1) + ")"))));
-        return ;
+        return;
     case "D" :
-        var match = x._0;
+        let match = x._0;
         console.log("printVariantWithPayloads", "D((" + (String(match[0]) + (", " + (String(match[1]) + "))"))));
-        return ;
+        return;
     case "E" :
         console.log("printVariantWithPayloads", "E(" + (String(x._0) + (", " + (x._1 + (", " + (String(x._2) + ")"))))));
-        return ;
+        return;
     
   }
 }
@@ -83,14 +83,14 @@ function testVariant1Object(x) {
 }
 
 export {
-  testWithPayload ,
-  printVariantWithPayload ,
-  testManyPayloads ,
-  printManyPayloads ,
-  testSimpleVariant ,
-  testVariantWithPayloads ,
-  printVariantWithPayloads ,
-  testVariant1Int ,
-  testVariant1Object ,
+  testWithPayload,
+  printVariantWithPayload,
+  testManyPayloads,
+  printManyPayloads,
+  testSimpleVariant,
+  testVariantWithPayloads,
+  printVariantWithPayloads,
+  testVariant1Int,
+  testVariant1Object,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Warnings.res.js b/jscomp/gentype_tests/typescript-react-example/src/Warnings.res.js
index 85e08c2ae4..9570aef6d8 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Warnings.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Warnings.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 42;
+let x = 42;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/Wrapper.res.js b/jscomp/gentype_tests/typescript-react-example/src/Wrapper.res.js
index e49a9a2be3..cfb651f571 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/Wrapper.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/Wrapper.res.js
@@ -1,8 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
-'use strict';
 
 
-let v = 3;
+let MyModuleAlias;
 
-exports.v = v;
+export {
+  MyModuleAlias,
+}
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/counter.res.js b/jscomp/gentype_tests/typescript-react-example/src/counter.res.js
index 10458c1307..0cc8041a72 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/counter.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/counter.res.js
@@ -1,12 +1,12 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var b = {
+let b = {
   TAG: "A",
   _0: 12
 };
 
 export {
-  b ,
+  b,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/location/location.res.js b/jscomp/gentype_tests/typescript-react-example/src/location/location.res.js
index 85e08c2ae4..9570aef6d8 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/location/location.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/location/location.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 42;
+let x = 42;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/nested/Tuples.res.js b/jscomp/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
index 6aaff47bdc..41de58327c 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/nested/Tuples.res.js
@@ -8,14 +8,14 @@ function testTuple(param) {
 
 function computeArea(param) {
   return Math.imul(Math.imul(param[0], param[1]), Belt_Option.mapWithDefault(param[2], 1, (function (n) {
-                    return n;
-                  })));
+    return n;
+  })));
 }
 
 function computeAreaWithIdent(param) {
   return Math.imul(Math.imul(param[0], param[1]), Belt_Option.mapWithDefault(param[2], 1, (function (n) {
-                    return n;
-                  })));
+    return n;
+  })));
 }
 
 function computeAreaNoConverters(param) {
@@ -24,10 +24,10 @@ function computeAreaNoConverters(param) {
 
 function coord2d(x, y) {
   return [
-          x,
-          y,
-          undefined
-        ];
+    x,
+    y,
+    undefined
+  ];
 }
 
 function getFirstName(param) {
@@ -36,37 +36,37 @@ function getFirstName(param) {
 
 function marry(first, second) {
   return [
-          first,
-          second
-        ];
+    first,
+    second
+  ];
 }
 
 function changeSecondAge(param) {
-  var second = param[1];
+  let second = param[1];
   return [
-          param[0],
-          {
-            name: second.name,
-            age: second.age + 1 | 0
-          }
-        ];
+    param[0],
+    {
+      name: second.name,
+      age: second.age + 1 | 0
+    }
+  ];
 }
 
-var origin = [
+let origin = [
   0,
   0,
   0
 ];
 
 export {
-  testTuple ,
-  origin ,
-  computeArea ,
-  computeAreaWithIdent ,
-  computeAreaNoConverters ,
-  coord2d ,
-  getFirstName ,
-  marry ,
-  changeSecondAge ,
+  testTuple,
+  origin,
+  computeArea,
+  computeAreaWithIdent,
+  computeAreaNoConverters,
+  coord2d,
+  getFirstName,
+  marry,
+  changeSecondAge,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/nested/Types.res.js b/jscomp/gentype_tests/typescript-react-example/src/nested/Types.res.js
index ef7c09ca98..ecfa09bcab 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/nested/Types.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/nested/Types.res.js
@@ -6,10 +6,10 @@ import * as Belt_Option from "rescript/lib/es6/belt_Option.js";
 
 function swap(tree) {
   return {
-          label: tree.label,
-          left: Belt_Option.map(tree.right, swap),
-          right: Belt_Option.map(tree.left, swap)
-        };
+    label: tree.label,
+    left: Belt_Option.map(tree.right, swap),
+    right: Belt_Option.map(tree.left, swap)
+  };
 }
 
 function selfRecursiveConverter(param) {
@@ -36,7 +36,7 @@ function testConvertLocation(x) {
   return x;
 }
 
-var testMarshalFields = {
+let testMarshalFields = {
   _rec: "rec",
   _switch: "_switch",
   switch: "switch",
@@ -56,15 +56,15 @@ function testInstantiateTypeParameter(x) {
   return x;
 }
 
-var currentTime = new Date();
+let currentTime = new Date();
 
-var optFunction = (function (param) {
-    return 3;
-  });
+let optFunction = (function (param) {
+  return 3;
+});
 
-var ObjectId = {};
+let ObjectId = {};
 
-var someIntList = {
+let someIntList = {
   hd: 1,
   tl: {
     hd: 2,
@@ -75,38 +75,38 @@ var someIntList = {
   }
 };
 
-var map = List.map;
+let map = List.map;
 
-var stringT = "a";
+let stringT = "a";
 
-var jsStringT = "a";
+let jsStringT = "a";
 
-var jsString2T = "a";
+let jsString2T = "a";
 
-var i64Const = [
+let i64Const = [
   0,
   34
 ];
 
 export {
-  someIntList ,
-  map ,
-  swap ,
-  selfRecursiveConverter ,
-  mutuallyRecursiveConverter ,
-  testFunctionOnOptionsAsArgument ,
-  stringT ,
-  jsStringT ,
-  jsString2T ,
-  jsonStringify ,
-  testConvertNull ,
-  testConvertLocation ,
-  testMarshalFields ,
-  setMatch ,
-  testInstantiateTypeParameter ,
-  currentTime ,
-  i64Const ,
-  optFunction ,
-  ObjectId ,
+  someIntList,
+  map,
+  swap,
+  selfRecursiveConverter,
+  mutuallyRecursiveConverter,
+  testFunctionOnOptionsAsArgument,
+  stringT,
+  jsStringT,
+  jsString2T,
+  jsonStringify,
+  testConvertNull,
+  testConvertLocation,
+  testMarshalFields,
+  setMatch,
+  testInstantiateTypeParameter,
+  currentTime,
+  i64Const,
+  optFunction,
+  ObjectId,
 }
 /* currentTime Not a pure module */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/404.res.js b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/404.res.js
index b48a2a7cc0..f1c5aa235f 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/404.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/404.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 123;
+let x = 123;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/AppModal.web.res.js b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/AppModal.web.res.js
index b48a2a7cc0..f1c5aa235f 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/AppModal.web.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/AppModal.web.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 123;
+let x = 123;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/_under.res.js b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/_under.res.js
index b48a2a7cc0..f1c5aa235f 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/_under.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/_under.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 123;
+let x = 123;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */
diff --git a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/with_underscore.res.js b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/with_underscore.res.js
index b48a2a7cc0..f1c5aa235f 100644
--- a/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/with_underscore.res.js
+++ b/jscomp/gentype_tests/typescript-react-example/src/strange_file_names/with_underscore.res.js
@@ -1,9 +1,9 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 
-var x = 123;
+let x = 123;
 
 export {
-  x ,
+  x,
 }
 /* No side effect */