feature: improve support of ExportNamespaceSpecifiers

lib/printer.ts

@@ -2960,13 +2960,17 @@ function printExportDeclaration(path: any, options: any, print: any) {
           parts.push("{", lines, "}");
         }
       }
-    } else {
+    } else if (decl.specifiers[0].type === 'ExportNamespaceSpecifier') {
       parts.push(
-        shouldPrintSpaces ? "{ " : "{",
         fromString(", ").join(path.map(print, "specifiers")),
-        shouldPrintSpaces ? " }" : "}",
       );
-    }
+    } else {
+    parts.push(
+      shouldPrintSpaces ? "{ " : "{",
+      fromString(", ").join(path.map(print, "specifiers")),
+      shouldPrintSpaces ? " }" : "}",
+    );
+  }
 
     if (decl.source) {
       parts.push(

package.json

@@ -51,6 +51,8 @@
     "@babel/core": "7.14.8",
     "@babel/parser": "7.14.8",
     "@babel/preset-env": "7.16.11",
+    "@types/babel__template": "^7.4.1",
+    "@types/babel__traverse": "^7.18.1",
     "@types/esprima": "4.0.3",
     "@types/glob": "7.2.0",
     "@types/mocha": "8.2.0",

test/babel.ts

@@ -3,6 +3,9 @@ import * as recast from "../main";
 const n = recast.types.namedTypes;
 const b = recast.types.builders;
 import { EOL as eol } from "os";
+import traverse, {NodePath, Node} from '@babel/traverse';
+import template from '@babel/template';
+
 const nodeMajorVersion = parseInt(process.versions.node, 10);
 
 describe("Babel", function () {
@@ -454,4 +457,21 @@ describe("Babel", function () {
       ["class A {", "  declare public readonly x;", "}"].join(eol),
     );
   });
+
+  it("should not add curly braces in ExportNamedDeclaration used with ExportNamespaceSpecifier", function () {
+    const code = 'export * as fs2 from "fs/promises"';
+    const ast = recast.parse(code, parseOptions);
+
+    traverse(ast, {
+      ExportNamedDeclaration(path: NodePath) {
+        path.replaceWith(template.ast('export * as fs from "xx"') as Node);
+        path.stop();
+      }
+    })
+
+    assert.strictEqual(
+      recast.print(ast).code,
+      'export * as fs from "xx";'
+    );
+  });
 });