From 0c5fae2faa251e3c2459071cacc41408ef56150d Mon Sep 17 00:00:00 2001
From: Sven SAULEAU <xtuc@users.noreply.github.com>
Date: Wed, 13 Sep 2017 05:59:00 +0200
Subject: [PATCH] Make sure source type is module when parsing .mjs (#5700)

* feat: force source type module for mjs extension

* style: fix lint
---
 packages/babel-core/src/config/option-manager.js |  4 ++++
 packages/babel-core/test/option-manager.js       | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/packages/babel-core/src/config/option-manager.js b/packages/babel-core/src/config/option-manager.js
index 1d1f1a79b4..b42199830b 100644
--- a/packages/babel-core/src/config/option-manager.js
+++ b/packages/babel-core/src/config/option-manager.js
@@ -195,6 +195,10 @@ class OptionManager {
 
     const basenameRelative = path.basename(opts.filenameRelative);
 
+    if (path.extname(opts.filenameRelative) === ".mjs") {
+      opts.sourceType = "module";
+    }
+
     defaults(opts, {
       sourceFileName: basenameRelative,
       sourceMapTarget: basenameRelative,
diff --git a/packages/babel-core/test/option-manager.js b/packages/babel-core/test/option-manager.js
index 3868d456fa..5358b2f2f2 100644
--- a/packages/babel-core/test/option-manager.js
+++ b/packages/babel-core/test/option-manager.js
@@ -44,6 +44,17 @@ describe("option-manager", () => {
     });
   });
 
+  describe("source type", function() {
+    it("should set module for .mjs extension", () => {
+      const config = manageOptions({
+        sourceType: "program",
+        filename: "foo.mjs",
+      });
+
+      assert.equal(config.options.sourceType, "module");
+    });
+  });
+
   describe("presets", function() {
     function presetTest(name) {
       it(name, function() {