React instead of ReactDOM for fragment

Author: mununki

jscomp/syntax/src/reactjs_jsx_v4.ml

@@ -1358,6 +1358,7 @@ let expr ~config mapper expression =
       in
       let childrenExpr = transformChildrenIfList ~mapper listItems in
       let recordOfChildren children =
+        (* FIXME: missing loc *)
         Exp.record [(Location.mknoloc (Lident "children"), children)] None
       in
       let args =
@@ -1390,7 +1391,11 @@ let expr ~config mapper expression =
             Exp.ident ~loc {loc; txt = Ldot (Lident "React", "jsxs")}
           else Exp.ident ~loc {loc; txt = Ldot (Lident "React", "jsx")}
         | "classic" | _ ->
-          Exp.ident ~loc {loc; txt = Ldot (Lident "ReactDOM", "createElement")})
+          if countOfChildren childrenExpr > 1 then
+            Exp.ident ~loc
+              {loc; txt = Ldot (Lident "React", "createElementVariadic")}
+          else
+            Exp.ident ~loc {loc; txt = Ldot (Lident "React", "createElement")})
         args)
   (* Delegate to the default mapper, a deep identity traversal *)
   | e -> default_mapper.expr mapper e

jscomp/syntax/tests/ppx/react/expected/fragment.res.txt

@@ -1,12 +1,12 @@
 @@jsxConfig({version: 4, mode: "classic"})
 
-let _ = ReactDOM.createElement(React.fragment, [])
-let _ = ReactDOM.createElement(React.fragment, [ReactDOM.createDOMElementVariadic("div", [])])
-let _ = ReactDOM.createElement(
+let _ = React.createElement(React.fragment, [])
+let _ = React.createElement(React.fragment, [ReactDOM.createDOMElementVariadic("div", [])])
+let _ = React.createElementVariadic(
   React.fragment,
   [ReactDOM.createDOMElementVariadic("div", []), ReactDOM.createDOMElementVariadic("div", [])],
 )
-let _ = ReactDOM.createElement(React.fragment, [ReactDOM.createElement(React.fragment, [])])
+let _ = React.createElement(React.fragment, [React.createElement(React.fragment, [])])
 let _ = React.createElement(Z.make, {})
 let _ = React.createElement(Z.make, {children: ReactDOM.createDOMElementVariadic("div", [])})
 let _ = React.createElementVariadic(

jscomp/syntax/tests/ppx/react/expected/noPropsWithKey.res.txt

@@ -22,7 +22,7 @@ module V4C = {
   type props = {}
 
   let make = (_: props) =>
-    ReactDOM.createElement(
+    React.createElementVariadic(
       React.fragment,
       [
         JsxPPXReactSupport.createElementWithKey(~key="k", V4CA.make, {}),

jscomp/syntax/tests/ppx/react/expected/removedKeyProp.res.txt

@@ -14,7 +14,7 @@ module Foo = {
 module HasChildren = {
   type props<'children> = {children: 'children}
 
-  let make = ({children, _}: props<_>) => ReactDOM.createElement(React.fragment, [children])
+  let make = ({children, _}: props<_>) => React.createElement(React.fragment, [children])
   let make = {
     let \"RemovedKeyProp$HasChildren" = (props: props<_>) => make(props)
 
@@ -24,7 +24,7 @@ module HasChildren = {
 type props = {}
 
 let make = (_: props) =>
-  ReactDOM.createElement(
+  React.createElementVariadic(
     React.fragment,
     [
       JsxPPXReactSupport.createElementWithKey(~key="k", Foo.make, {x: "x", y: "y"}),