Handle react fragment in top level.

Fixes #229.

ecmascript/transforms/src/react/jsx/mod.rs

@@ -266,6 +266,14 @@ impl Fold<Expr> for Jsx {
                 // <div></div> => React.createElement('div', null);
                 self.jsx_elem_to_expr(el)
             }
+            Expr::Paren(ParenExpr {
+                expr: box Expr::JSXFragment(frag),
+                ..
+            })
+            | Expr::JSXFragment(frag) => {
+                // <></> => React.createElement(React.Fragment, null);
+                self.jsx_frag_to_expr(frag)
+            }
             _ => expr,
         }
     }

ecmascript/transforms/src/react/jsx/tests.rs

@@ -1024,3 +1024,19 @@ var div = React.createElement(Component, Object.assign({}, props, {
 }));
 "#
 );
+
+test!(
+    ::swc_ecma_parser::Syntax::Es(::swc_ecma_parser::EsConfig {
+        jsx: true,
+        ..Default::default()
+    }),
+    |_| tr(Options {
+        use_builtins: true,
+        ..Default::default()
+    },),
+    issue_229,
+    "const a = <>test</>
+const b = <div>test</div>",
+    "const a = React.createElement(React.Fragment, null, 'test');
+const b = React.createElement('div', null, 'test');"
+);