From a262e99abd7db0f36bd0c3ce30f1c5e02d0608a8 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Tue, 7 Jul 2015 10:52:43 +0100
Subject: [PATCH] strip flow directives in flow transformer - fixes #1934

---
 src/babel/transformation/transformers/other/flow.js      | 7 +++++++
 .../transformation/flow/strip-directive/actual.js        | 9 +++++++++
 .../transformation/flow/strip-directive/expected.js      | 1 +
 3 files changed, 17 insertions(+)
 create mode 100644 test/core/fixtures/transformation/flow/strip-directive/actual.js
 create mode 100644 test/core/fixtures/transformation/flow/strip-directive/expected.js

diff --git a/src/babel/transformation/transformers/other/flow.js b/src/babel/transformation/transformers/other/flow.js
index f058924a59..84dda2a7d5 100644
--- a/src/babel/transformation/transformers/other/flow.js
+++ b/src/babel/transformation/transformers/other/flow.js
@@ -5,6 +5,13 @@ export var metadata = {
 };
 
 export var visitor = {
+  Program(node, parent, scope, file) {
+    for (var comment of (file.ast.comments: Array)) {
+      if (comment.value.indexOf("@flow") >= 0) {
+        comment._displayed = true;
+      }
+    }
+  },
   Flow() {
     this.dangerouslyRemove();
   },
diff --git a/test/core/fixtures/transformation/flow/strip-directive/actual.js b/test/core/fixtures/transformation/flow/strip-directive/actual.js
new file mode 100644
index 0000000000..575f234bbc
--- /dev/null
+++ b/test/core/fixtures/transformation/flow/strip-directive/actual.js
@@ -0,0 +1,9 @@
+/*@flow*/
+
+/* @flow */
+
+/**
+ * @flow
+ */
+
+foo();
diff --git a/test/core/fixtures/transformation/flow/strip-directive/expected.js b/test/core/fixtures/transformation/flow/strip-directive/expected.js
new file mode 100644
index 0000000000..a280f9a5cc
--- /dev/null
+++ b/test/core/fixtures/transformation/flow/strip-directive/expected.js
@@ -0,0 +1 @@
+foo();