Only print space when there are props

Author: nojaf

compiler/ml/ast_mapper_from0.ml

@@ -433,7 +433,6 @@ module E = struct
     | Pexp_construct ({txt = Longident.Lident "[]" | Longident.Lident "::"}, _)
       when has_jsx_attribute () ->
       let attrs = attrs |> List.filter (fun ({txt}, _) -> txt <> "JSX") in
-      (* TODO: support spread *)
       jsx_fragment ~loc ~attrs loc.loc_start (map_jsx_children sub e)
         loc.loc_end
     | Pexp_construct (lid, arg) -> (

compiler/syntax/src/res_printer.ml

@@ -4469,7 +4469,8 @@ and print_jsx_container_tag ~state tag_name props
                 print_comments
                   (Doc.concat [Doc.less_than; name])
                   cmt_tbl tag_name.Asttypes.loc;
-                Doc.space;
+                (if not (List.is_empty formatted_props) then Doc.space
+                 else Doc.nil);
                 (* todo: might not be needed if no props?*)
                 Doc.join formatted_props ~sep:Doc.space;
                 (* if tag A has trailing comments then put > on the next line