From eac1b1cea9e3b2a3741fb9f557a833c48f00aa74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hua=CC=81ng=20Ju=CC=80nlia=CC=80ng?= <i@jhuang.me>
Date: Fri, 5 Jul 2019 15:19:38 -0400
Subject: [PATCH] fix: export should not be erased when mixed with
 `proposal-export-default-from`

---
 packages/babel-plugin-transform-typescript/src/index.js     | 6 +++---
 .../test/fixtures/exports/export-default-from/input.mjs     | 1 +
 .../test/fixtures/exports/export-default-from/options.json  | 3 +++
 .../test/fixtures/exports/export-default-from/output.mjs    | 2 ++
 4 files changed, 9 insertions(+), 3 deletions(-)
 create mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/input.mjs
 create mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/options.json
 create mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/output.mjs

diff --git a/packages/babel-plugin-transform-typescript/src/index.js b/packages/babel-plugin-transform-typescript/src/index.js
index 8498da7afa30..79ca001029a4 100644
--- a/packages/babel-plugin-transform-typescript/src/index.js
+++ b/packages/babel-plugin-transform-typescript/src/index.js
@@ -101,7 +101,7 @@ export default declare(
             !path.node.source &&
             path.node.specifiers.length > 0 &&
             !path.node.specifiers.find(exportSpecifier =>
-              path.scope.hasOwnBinding(exportSpecifier.local.name),
+              path.scope.hasBinding(exportSpecifier.local.name),
             )
           ) {
             path.remove();
@@ -112,7 +112,7 @@ export default declare(
           // remove type exports
           if (
             !path.parent.source &&
-            !path.scope.hasOwnBinding(path.node.local.name)
+            !path.scope.hasBinding(path.node.local.name)
           ) {
             path.remove();
           }
@@ -122,7 +122,7 @@ export default declare(
           // remove whole declaration if it's exporting a TS type
           if (
             t.isIdentifier(path.node.declaration) &&
-            !path.scope.hasOwnBinding(path.node.declaration.name)
+            !path.scope.hasBinding(path.node.declaration.name)
           ) {
             path.remove();
           }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/input.mjs b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/input.mjs
new file mode 100644
index 000000000000..0ae857f77a46
--- /dev/null
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/input.mjs
@@ -0,0 +1 @@
+export foo from "./foo";
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/options.json
new file mode 100644
index 000000000000..56ccd6e58102
--- /dev/null
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["proposal-export-default-from", ["transform-typescript", { "allowNamespaces": true }]]
+}
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/output.mjs b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/output.mjs
new file mode 100644
index 000000000000..8a73f6ac4bbc
--- /dev/null
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export-default-from/output.mjs
@@ -0,0 +1,2 @@
+import _foo from "./foo";
+export { _foo as foo };