From 3fa4f53d0acb933c1864da7a51095a497545a187 Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Mon, 8 Oct 2018 05:30:02 +0200
Subject: [PATCH] System module format - fixes function hoisting failure case
 (#8820)

* failing test case

* fix function hoist bug
---
 .../src/index.js                              | 19 +++++++++++++++++--
 .../systemjs/export-fn-decl/input.mjs         | 10 ++++++++++
 .../systemjs/export-fn-decl/output.mjs        | 18 ++++++++++++++++++
 3 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/input.mjs
 create mode 100644 packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/output.mjs

diff --git a/packages/babel-plugin-transform-modules-systemjs/src/index.js b/packages/babel-plugin-transform-modules-systemjs/src/index.js
index 5f93094be5..242d132163 100644
--- a/packages/babel-plugin-transform-modules-systemjs/src/index.js
+++ b/packages/babel-plugin-transform-modules-systemjs/src/index.js
@@ -332,8 +332,23 @@ export default declare((api, options) => {
                     const nodes = [];
 
                     for (const specifier of specifiers) {
-                      // only globals exported this way
-                      if (!path.scope.getBinding(specifier.local.name)) {
+                      const binding = path.scope.getBinding(
+                        specifier.local.name,
+                      );
+                      // hoisted function export
+                      if (
+                        binding &&
+                        t.isFunctionDeclaration(binding.path.node)
+                      ) {
+                        beforeBody.push(
+                          buildExportCall(
+                            specifier.exported.name,
+                            t.cloneNode(specifier.local),
+                          ),
+                        );
+                      }
+                      // only globals also exported this way
+                      else if (!binding) {
                         nodes.push(
                           buildExportCall(
                             specifier.exported.name,
diff --git a/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/input.mjs b/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/input.mjs
new file mode 100644
index 0000000000..3c230f1867
--- /dev/null
+++ b/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/input.mjs
@@ -0,0 +1,10 @@
+var testProp = 'test property';
+
+function testFunc() {
+  return 'test function';
+}
+
+export {
+  testFunc,
+  testProp
+};
diff --git a/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/output.mjs b/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/output.mjs
new file mode 100644
index 0000000000..c3c2159be3
--- /dev/null
+++ b/packages/babel-plugin-transform-modules-systemjs/test/fixtures/systemjs/export-fn-decl/output.mjs
@@ -0,0 +1,18 @@
+System.register([], function (_export, _context) {
+  "use strict";
+
+  var testProp;
+
+  function testFunc() {
+    return 'test function';
+  }
+
+  _export("testFunc", testFunc);
+
+  return {
+    setters: [],
+    execute: function () {
+      _export("testProp", testProp = 'test property');
+    }
+  };
+});
\ No newline at end of file