From 4d9edec4e1e2dffb5d5d8f6bfd0c3b02d181bdbd Mon Sep 17 00:00:00 2001
From: Brian Ng <bng412@gmail.com>
Date: Thu, 13 Apr 2017 09:10:08 -0500
Subject: [PATCH] Fix trailing comma for rest element in Babylon (#1230)

---
 src/printer.js           | 7 +++++--
 tests/rest/jsfmt.spec.js | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/printer.js b/src/printer.js
index d286ca5c..f1da58fc 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -706,8 +706,11 @@ function genericPrintNoParens(path, options, print, args) {
       });
 
       const lastElem = util.getLast(n[propertiesField]);
-      const canHaveTrailingComma = !(lastElem &&
-        lastElem.type === "RestProperty");
+
+      const canHaveTrailingComma = !(
+        lastElem &&
+        (lastElem.type === "RestProperty" || lastElem.type === "RestElement")
+      );
 
       const shouldBreak =
         n.type !== "ObjectPattern" &&
diff --git a/tests/rest/jsfmt.spec.js b/tests/rest/jsfmt.spec.js
index a4f98d3f..1f7d49d1 100644
--- a/tests/rest/jsfmt.spec.js
+++ b/tests/rest/jsfmt.spec.js
@@ -1 +1 @@
-run_spec(__dirname, { trailingComma: "all" });
+run_spec(__dirname, { trailingComma: "all" }, ["babylon"]);