From 59c9f473ae71b68d24bb1d959c69c3795d83ae72 Mon Sep 17 00:00:00 2001
From: Felix Kling <felix.kling@gmx.net>
Date: Mon, 15 Dec 2014 22:33:47 -0800
Subject: [PATCH] Support async functions in export declarations

6to5 is able to transpile `export async function foo(){}` but acorn-6to5 is
unable to parse it.
---
 acorn.js           |  2 +-
 bin/acorn          |  1 +
 test/tests-6to5.js | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/acorn.js b/acorn.js
index 3aa7f661c7..570ec31b9b 100644
--- a/acorn.js
+++ b/acorn.js
@@ -3139,7 +3139,7 @@
   function parseExport(node) {
     next();
     // export var|const|let|function|class ...;
-    if (tokType === _var || tokType === _const || tokType === _let || tokType === _function || tokType === _class) {
+    if (tokType === _var || tokType === _const || tokType === _let || tokType === _function || tokType === _class || tokType === _name && tokVal === 'async') {
       node.declaration = parseStatement();
       node['default'] = false;
       node.specifiers = null;
diff --git a/bin/acorn b/bin/acorn
index 2a226da063..dd5baea012 100755
--- a/bin/acorn
+++ b/bin/acorn
@@ -20,6 +20,7 @@ for (var i = 2; i < process.argv.length; ++i) {
   else if (arg == "--ecma3") options.ecmaVersion = 3;
   else if (arg == "--ecma5") options.ecmaVersion = 5;
   else if (arg == "--ecma6") options.ecmaVersion = 6;
+  else if (arg == "--ecma7") options.ecmaVersion = 7;
   else if (arg == "--strictSemicolons") options.strictSemicolons = true;
   else if (arg == "--locations") options.locations = true;
   else if (arg == "--silent") silent = true;
diff --git a/test/tests-6to5.js b/test/tests-6to5.js
index a0a24fe647..708937b9cd 100644
--- a/test/tests-6to5.js
+++ b/test/tests-6to5.js
@@ -1901,6 +1901,45 @@ test('var obj = { async() {} };', {
   ecmaVersion: 7
 });
 
+test('export async function foo(){}', {
+  "type": "Program",
+  "start": 0,
+  "end": 29,
+  "body": [{
+    "type": "ExportDeclaration",
+    "start": 0,
+    "end": 29,
+    "declaration": {
+      "type": "FunctionDeclaration",
+      "start": 7,
+      "end": 29,
+      "id": {
+        "type": "Identifier",
+        "start": 22,
+        "end": 25,
+        "name": "foo"
+      },
+      "params": [],
+      "defaults": [],
+      "rest": null,
+      "generator": false,
+      "async": true,
+      "body": {
+        "type": "BlockStatement",
+        "start": 27,
+        "end": 29,
+        "body": []
+      },
+      "expression": false
+    },
+    "default": false,
+    "specifiers": null,
+    "source": null
+  }]
+}, {
+  ecmaVersion: 7
+});
+
 // ES7: Abstract references
 
 test('foo::bar;', {