From 8a526274567a0c364a4c91d7fbc5c7585e81445a Mon Sep 17 00:00:00 2001
From: Airat Aminev <airato.a@gmail.com>
Date: Thu, 23 May 2019 13:49:36 -0700
Subject: [PATCH] fix(typescript): erase default export if exporting a TS type

---
 .../babel-plugin-transform-typescript/src/index.js     | 10 ++++++++++
 .../test/fixtures/declarations/erased/input.mjs        |  1 +
 2 files changed, 11 insertions(+)

diff --git a/packages/babel-plugin-transform-typescript/src/index.js b/packages/babel-plugin-transform-typescript/src/index.js
index b2a8c0d2afce..4f1a0a1fa78b 100644
--- a/packages/babel-plugin-transform-typescript/src/index.js
+++ b/packages/babel-plugin-transform-typescript/src/index.js
@@ -156,6 +156,16 @@ export default declare((api, { jsxPragma = "React" }) => {
         }
       },
 
+      ExportDefaultDeclaration(path, { exportableTSNames }) {
+        // remove whole declaration if it's exporting a TS type
+        if (
+          t.isIdentifier(path.node.declaration) &&
+          exportableTSNames.has(path.node.declaration.name)
+        ) {
+          path.remove();
+        }
+      },
+
       TSDeclareFunction(path) {
         path.remove();
       },
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/declarations/erased/input.mjs b/packages/babel-plugin-transform-typescript/test/fixtures/declarations/erased/input.mjs
index b54970d889a5..e83413bd77d1 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/declarations/erased/input.mjs
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/declarations/erased/input.mjs
@@ -42,6 +42,7 @@ function foo() {}
 export { II3 as default, AA2 as A, BB2 as BB3, foo }; // only BB2 and foo
 
 // export an interface before declaration
+export default Bar;
 export { Bar } // everything removed
 export { Bar as Bar2, C2 as C4 } // only C4
 interface Bar {}